cleanup
replaced the license by two library-specific licenses
built an interface between renderers and controllers and partially
implemented it for nitro
game is now listenable for ticks. That's the first step to split up the
game in multiple states (playing, menu...)
postionables now have defaultcolliders and -renderers to avoid having
nullpointerexceptions
some documentation
moved loadScaledSpriteSheet to the top-most renderer-class as it is
relevant for all renderers
stub for first projectile (bullet for nitro) for further
destruction-testing including the renderer
inserted the middle-class MoveableRenderer between PositionableRenderer
and MechRenderer to comply with the design on logic-side (Mech is a
Movable is a Postionable)