Update composer.json

Raise php minimal version + switch to psr-4

Author: ngodfraind

composer.json

@@ -13,11 +13,10 @@
         }
     ],
     "require": {
-        "php": ">=5.4.1",
+        "php": ">=5.5",
         "claroline/core-bundle": "~6.0"
     },
     "autoload": {
-        "psr-0": { "Claroline\\ActivityToolBundle": "" }
-    },
-    "target-dir": "Claroline/ActivityToolBundle"
+        "psr-4": { "Claroline\\ActivityToolBundle\\": "" }
+    }
 }