INT: preparation to make light sources Transformable
INT: LightSource are now Transformable ==> position is reused
INT: fixed the aimAt function,added alignWith in Transformable
INT: LightSource now uses the forward() vecror as direction
INT: simplified the light source system
INT: started a "scene" class
INT: transformable can now be attached to each other;
INT: started component-ization of the whole game structure
INT: fps counter, window/mouse/keyboard control are now components
INT: extracted the controls to their own headers
INT: implemented the derivation-less polymorphism from Sean Parent's talk
"inheritance is the base class of all evil"