Removed unneccesary initalisation
javadoc & small refactoring
Refactoring & javadoc
Added entity spawner
Added new chunk generator for testing single blocks
Updated older chunk generators
Improved entitySpawner
Added button functionality
Separated ids of GameObjects' subclasses

- There is a new category character before the image
- changed file/ folder names of sprites with adding "prelit" and
removed "unlit"
Separated offsetlist and namelist
Reduced border artifacts and updated sprite sheet files
Entity spawner spawns a player entity.

This reproduces bug #21.