add simple EventHandler to Viewer that will soon deal with incoming events unrelated to navigation
ref #4 rename GodManipulator to GodNavigation and GodEventHandler to GodManipulator
rename parameters of manipulator/navigation constructors to match new names
merge master into eventHandler
seperate actual content of the world from game class

* game class is responsible for meta game logic like game start/end/pause and proper handling of the game loop
* world class holds the actual content of the world like terrain, objects or the physic
add simple interaction to GodManipulator

pressing F causes the World to create a standard ball
add empty handle functions to GodManipulator.

To handle a specific event, add it to it's corresponding handle* function in the GodManipulator.
Merge pull request #7 from lanice/eventHandler

Seperation of Game class (META game logic) and World class (game content/logic) plus simple EventHandler