Use PSR-4 instead of PSR-0 autoloader

Author: henriquemoody

composer.json

@@ -7,16 +7,20 @@
         {
             "name": "Kinn Coelho Julião",
             "email": "[email protected]"
+        },
+        {
+            "name": "Henrique Moody",
+            "email": "[email protected]"
         }
     ],
     "autoload": {
-        "psr-0": {
-            "PHPFluent\\EventManager": "src/"
+        "psr-4": {
+            "PHPFluent\\EventManager\\": "src/PHPFluent/EventManager"
         }
     },
     "require-dev": {
         "phpmd/phpmd" : "~1.5",
         "phpunit/phpunit": "~4.1",
         "squizlabs/php_codesniffer": "~1.5"
     }
-}
+}