[BUGFIX] Bugfixes and optimisations

- When no parameter is recieved, router now returns null instead of empty
  string.
- json method in Response class now stops response after execution.
- Updated composer.json with correct autoload.

src/Pecee/SimpleRouter/RouterRoute.php

@@ -90,8 +90,8 @@ class RouterRoute extends RouterEntry {
                             }
                         }
 
-                        // Add parameter value
-                        $parameters[$parameter] = $parameterValue;
+                        // Add parameter value, if it doesn't exist - replace it with null value
+                        $parameters[$parameter] = ($parameterValue === '') ? null : $parameterValue;
                     }
                 }
             }
@@ -160,5 +160,4 @@ class RouterRoute extends RouterEntry {
         return parent::setSettings($settings);
     }
 
-
 }