diff --git a/composer.json b/composer.json
index 7b814fc..2428cae 100644
--- a/composer.json
+++ b/composer.json
@@ -31,7 +31,7 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "~5",
+        "phpunit/phpunit": "~4",
         "mikey179/vfsStream": "^1.6"
     }
 }
diff --git a/composer.lock b/composer.lock
index bd9df0c..289f06a 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,8 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "hash": "aa9d5f6529da41cf53c5d85dfaaaa816",
-    "content-hash": "1f5518d6e2b0fd25d12231b7b7beb910",
+    "hash": "809106d52bafeb022748eef6435db18d",
+    "content-hash": "1b6edd235a180dff6a9d5d67adb9c01c",
     "packages": [
         {
             "name": "guzzlehttp/guzzle",
@@ -1080,40 +1080,39 @@
         },
         {
             "name": "phpunit/php-code-coverage",
-            "version": "4.0.1",
+            "version": "2.2.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/php-code-coverage.git",
-                "reference": "5f3f7e736d6319d5f1fc402aff8b026da26709a3"
+                "reference": "eabf68b476ac7d0f73793aada060f1c1a9bf8979"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/php-code-coverage/zipball/5f3f7e736d6319d5f1fc402aff8b026da26709a3",
-                "reference": "5f3f7e736d6319d5f1fc402aff8b026da26709a3",
+                "url": "https://api.github.com/repos/sebastianbergmann/php-code-coverage/zipball/eabf68b476ac7d0f73793aada060f1c1a9bf8979",
+                "reference": "eabf68b476ac7d0f73793aada060f1c1a9bf8979",
                 "shasum": ""
             },
             "require": {
-                "php": "^5.6 || ^7.0",
+                "php": ">=5.3.3",
                 "phpunit/php-file-iterator": "~1.3",
                 "phpunit/php-text-template": "~1.2",
-                "phpunit/php-token-stream": "^1.4.2",
-                "sebastian/code-unit-reverse-lookup": "~1.0",
-                "sebastian/environment": "^1.3.2 || ^2.0",
-                "sebastian/version": "~1.0|~2.0"
+                "phpunit/php-token-stream": "~1.3",
+                "sebastian/environment": "^1.3.2",
+                "sebastian/version": "~1.0"
             },
             "require-dev": {
                 "ext-xdebug": ">=2.1.4",
-                "phpunit/phpunit": "^5.4"
+                "phpunit/phpunit": "~4"
             },
             "suggest": {
                 "ext-dom": "*",
-                "ext-xdebug": ">=2.4.0",
+                "ext-xdebug": ">=2.2.1",
                 "ext-xmlwriter": "*"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "4.0.x-dev"
+                    "dev-master": "2.2.x-dev"
                 }
             },
             "autoload": {
@@ -1139,7 +1138,7 @@
                 "testing",
                 "xunit"
             ],
-            "time": "2016-07-26 14:39:29"
+            "time": "2015-10-06 15:47:00"
         },
         {
             "name": "phpunit/php-file-iterator",
@@ -1324,51 +1323,40 @@
         },
         {
             "name": "phpunit/phpunit",
-            "version": "5.5.5",
+            "version": "4.8.27",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "a57126dc681b08289fef6ac96a48e30656f84350"
+                "reference": "c062dddcb68e44b563f66ee319ddae2b5a322a90"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/a57126dc681b08289fef6ac96a48e30656f84350",
-                "reference": "a57126dc681b08289fef6ac96a48e30656f84350",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/c062dddcb68e44b563f66ee319ddae2b5a322a90",
+                "reference": "c062dddcb68e44b563f66ee319ddae2b5a322a90",
                 "shasum": ""
             },
             "require": {
                 "ext-dom": "*",
                 "ext-json": "*",
-                "ext-libxml": "*",
-                "ext-mbstring": "*",
-                "ext-xml": "*",
-                "myclabs/deep-copy": "~1.3",
-                "php": "^5.6 || ^7.0",
+                "ext-pcre": "*",
+                "ext-reflection": "*",
+                "ext-spl": "*",
+                "php": ">=5.3.3",
                 "phpspec/prophecy": "^1.3.1",
-                "phpunit/php-code-coverage": "^4.0.1",
+                "phpunit/php-code-coverage": "~2.1",
                 "phpunit/php-file-iterator": "~1.4",
                 "phpunit/php-text-template": "~1.2",
                 "phpunit/php-timer": "^1.0.6",
-                "phpunit/phpunit-mock-objects": "^3.2",
+                "phpunit/phpunit-mock-objects": "~2.3",
                 "sebastian/comparator": "~1.1",
                 "sebastian/diff": "~1.2",
-                "sebastian/environment": "^1.3 || ^2.0",
+                "sebastian/environment": "~1.3",
                 "sebastian/exporter": "~1.2",
                 "sebastian/global-state": "~1.0",
-                "sebastian/object-enumerator": "~1.0",
-                "sebastian/resource-operations": "~1.0",
-                "sebastian/version": "~1.0|~2.0",
+                "sebastian/version": "~1.0",
                 "symfony/yaml": "~2.1|~3.0"
             },
-            "conflict": {
-                "phpdocumentor/reflection-docblock": "3.0.2"
-            },
-            "require-dev": {
-                "ext-pdo": "*"
-            },
             "suggest": {
-                "ext-tidy": "*",
-                "ext-xdebug": "*",
                 "phpunit/php-invoker": "~1.1"
             },
             "bin": [
@@ -1377,7 +1365,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "5.5.x-dev"
+                    "dev-master": "4.8.x-dev"
                 }
             },
             "autoload": {
@@ -1403,33 +1391,30 @@
                 "testing",
                 "xunit"
             ],
-            "time": "2016-09-21 14:40:13"
+            "time": "2016-07-21 06:48:14"
         },
         {
             "name": "phpunit/phpunit-mock-objects",
-            "version": "3.2.7",
+            "version": "2.3.8",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit-mock-objects.git",
-                "reference": "546898a2c0c356ef2891b39dd7d07f5d82c8ed0a"
+                "reference": "ac8e7a3db35738d56ee9a76e78a4e03d97628983"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit-mock-objects/zipball/546898a2c0c356ef2891b39dd7d07f5d82c8ed0a",
-                "reference": "546898a2c0c356ef2891b39dd7d07f5d82c8ed0a",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit-mock-objects/zipball/ac8e7a3db35738d56ee9a76e78a4e03d97628983",
+                "reference": "ac8e7a3db35738d56ee9a76e78a4e03d97628983",
                 "shasum": ""
             },
             "require": {
                 "doctrine/instantiator": "^1.0.2",
-                "php": "^5.6 || ^7.0",
-                "phpunit/php-text-template": "^1.2",
-                "sebastian/exporter": "^1.2"
-            },
-            "conflict": {
-                "phpunit/phpunit": "<5.4.0"
+                "php": ">=5.3.3",
+                "phpunit/php-text-template": "~1.2",
+                "sebastian/exporter": "~1.2"
             },
             "require-dev": {
-                "phpunit/phpunit": "^5.4"
+                "phpunit/phpunit": "~4.4"
             },
             "suggest": {
                 "ext-soap": "*"
@@ -1437,7 +1422,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.2.x-dev"
+                    "dev-master": "2.3.x-dev"
                 }
             },
             "autoload": {
@@ -1462,52 +1447,7 @@
                 "mock",
                 "xunit"
             ],
-            "time": "2016-09-06 16:07:45"
-        },
-        {
-            "name": "sebastian/code-unit-reverse-lookup",
-            "version": "1.0.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/sebastianbergmann/code-unit-reverse-lookup.git",
-                "reference": "c36f5e7cfce482fde5bf8d10d41a53591e0198fe"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/code-unit-reverse-lookup/zipball/c36f5e7cfce482fde5bf8d10d41a53591e0198fe",
-                "reference": "c36f5e7cfce482fde5bf8d10d41a53591e0198fe",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.6"
-            },
-            "require-dev": {
-                "phpunit/phpunit": "~5"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.0.x-dev"
-                }
-            },
-            "autoload": {
-                "classmap": [
-                    "src/"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Sebastian Bergmann",
-                    "email": "sebastian@phpunit.de"
-                }
-            ],
-            "description": "Looks up which function or method a line of code belongs to",
-            "homepage": "https://github.com/sebastianbergmann/code-unit-reverse-lookup/",
-            "time": "2016-02-13 06:45:14"
+            "time": "2015-10-02 06:51:40"
         },
         {
             "name": "sebastian/comparator",
@@ -1793,52 +1733,6 @@
             ],
             "time": "2015-10-12 03:26:01"
         },
-        {
-            "name": "sebastian/object-enumerator",
-            "version": "1.0.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/sebastianbergmann/object-enumerator.git",
-                "reference": "d4ca2fb70344987502567bc50081c03e6192fb26"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/object-enumerator/zipball/d4ca2fb70344987502567bc50081c03e6192fb26",
-                "reference": "d4ca2fb70344987502567bc50081c03e6192fb26",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.6",
-                "sebastian/recursion-context": "~1.0"
-            },
-            "require-dev": {
-                "phpunit/phpunit": "~5"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.0.x-dev"
-                }
-            },
-            "autoload": {
-                "classmap": [
-                    "src/"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Sebastian Bergmann",
-                    "email": "sebastian@phpunit.de"
-                }
-            ],
-            "description": "Traverses array structures and object graphs to enumerate all referenced objects",
-            "homepage": "https://github.com/sebastianbergmann/object-enumerator/",
-            "time": "2016-01-28 13:25:10"
-        },
         {
             "name": "sebastian/recursion-context",
             "version": "1.0.2",
@@ -1892,71 +1786,21 @@
             "homepage": "http://www.github.com/sebastianbergmann/recursion-context",
             "time": "2015-11-11 19:50:13"
         },
-        {
-            "name": "sebastian/resource-operations",
-            "version": "1.0.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/sebastianbergmann/resource-operations.git",
-                "reference": "ce990bb21759f94aeafd30209e8cfcdfa8bc3f52"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/resource-operations/zipball/ce990bb21759f94aeafd30209e8cfcdfa8bc3f52",
-                "reference": "ce990bb21759f94aeafd30209e8cfcdfa8bc3f52",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.6.0"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.0.x-dev"
-                }
-            },
-            "autoload": {
-                "classmap": [
-                    "src/"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Sebastian Bergmann",
-                    "email": "sebastian@phpunit.de"
-                }
-            ],
-            "description": "Provides a list of PHP built-in functions that operate on resources",
-            "homepage": "https://www.github.com/sebastianbergmann/resource-operations",
-            "time": "2015-07-28 20:34:47"
-        },
         {
             "name": "sebastian/version",
-            "version": "2.0.0",
+            "version": "1.0.6",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/version.git",
-                "reference": "c829badbd8fdf16a0bad8aa7fa7971c029f1b9c5"
+                "reference": "58b3a85e7999757d6ad81c787a1fbf5ff6c628c6"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/version/zipball/c829badbd8fdf16a0bad8aa7fa7971c029f1b9c5",
-                "reference": "c829badbd8fdf16a0bad8aa7fa7971c029f1b9c5",
+                "url": "https://api.github.com/repos/sebastianbergmann/version/zipball/58b3a85e7999757d6ad81c787a1fbf5ff6c628c6",
+                "reference": "58b3a85e7999757d6ad81c787a1fbf5ff6c628c6",
                 "shasum": ""
             },
-            "require": {
-                "php": ">=5.6"
-            },
             "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "2.0.x-dev"
-                }
-            },
             "autoload": {
                 "classmap": [
                     "src/"
@@ -1975,7 +1819,7 @@
             ],
             "description": "Library that helps with managing the version number of Git-hosted PHP projects",
             "homepage": "https://github.com/sebastianbergmann/version",
-            "time": "2016-02-04 12:56:52"
+            "time": "2015-06-21 13:59:46"
         },
         {
             "name": "webmozart/assert",