Update composer to 5.5.9 + Laravel 5.1

composer.json

@@ -24,12 +24,12 @@
         "source": "https://github.com/octobercms/october"
     },
     "require": {
-        "php": ">=5.4",
+        "php": ">=5.5.9",
         "october/rain": "~1.0",
         "october/system": "~1.0",
         "october/backend": "~1.0",
         "october/cms": "~1.0",
-        "laravel/framework": "5.0.*",
+        "laravel/framework": "5.1.*",
         "illuminate/html": "5.0.*"
     },
     "require-dev": {