Added a constructor to GameObject for copying a GameObject
Extended TickList to allow adding and removing objects and executing the tick action
Added the Burning wrapper class for wrapping around burning GameObjects
Removed getName() method from GameObject. Added before, but not needed after all
Added javadoc to the TickList class
Deleted TickList class, because it is not needed anymore
Added ActiveObject class for representing objects that are performing some action
Added Burning class for representing objects that are on fire
Added ActionExecutor class for handling the execution of actions using threads
Moved ActiveObject and Burning classes to gameobjects package, because they are game objects
Merge pull request #2 from ZimonD/ticklist

Handling of active objects using thread pool