Composer.json and phpunit changes (#14)

* Update composer.json

Require php >= 5.4 since traits and short array syntax are used.
Remove duplicate requirements from require-dev
Remove 'reference' from composer.json - Versions should be tagged

* Remove phpunit phar

phpunit will be installed in /bin directory with composer
Update composer to require phpunit
update documents to show new path

* Bump php version to >= 5.5 in composer.json

aligns php requrements with Guzzle

Author: Brandon

.gitignore

@@ -2,4 +2,5 @@
 vendor/
 selftests/
 config.php
+/bin
 composer.lock

README.md

@@ -20,7 +20,7 @@ $client = new \Iris\Client($login, $password, ['url' => 'https://api.inetwork.co
 
 ```bash
 $ composer install
-$ php phpunit.phar --bootstrap ./vendor/autoload.php tests/
+$ php ./bin/phpunit --bootstrap ./vendor/autoload.php tests/
 ```
 =======
 ## Examples

composer.json

@@ -4,18 +4,18 @@
     "description": "Bandwidth's Iris SDK for PHP",
     "keywords": ["iris","sdk","php"],
     "homepage": "http://dev.bandwidth.com",
-    "reference": "v0.0.10",
     "license": "MIT",
     "authors": [
     ],
     "require": {
-        "php": ">=5.3.0",
+        "php": ">=5.5",
         "guzzlehttp/guzzle": "~6.0"
     },
     "require-dev": {
-        "php": ">=5.3.0",
-        "phpunit/phpunit": "3.7.*",
-        "guzzlehttp/guzzle": "~6.0"
+        "phpunit/phpunit": "~4.7"
+    },
+    "config": {
+        "bin-dir": "bin"
     },
     "autoload": {
         "classmap": [