Close #4 and other Stuff

    - Eventmanager refactored. It now gets functions as listeners
    - Engine now requires all other lovetoys-files. Just require
      engine and you get the whole package
    - example adjusted to changes
    - Engine now has a own eventmanager and adds itself to it as a listener
      to the new events ComponentAdded and ComponentRemoved
    - Entitys now inform the engine about changes by firing Events
helperfunction from class.lua removed and added to eventmanager