Added InputManager
InputManager is kind of a helper-class that parses keyboard input and
provides functions for getting keys' states.
Added overload for drawing with coordinates as Vector3f to drawCube
Renamed Drawable -> IDrawable
Created abstract class Moveable for easily accessing WorldObjects'
moving functions.
Last _not-working_ commit, just to back up things, before changing
everything to use matrices.
TMP commit, idk
Raped up basically everything
Menu not working: new ui-system waits for programming, clean-up
required, now uses matrices and OpenGL 3.2