changed changenormals to return void
added spheremodel to the struct sphere
Added model to sphere struct
added files for ffrustrum culling
modified content of planetsim.c so we have an array of planets
Merged optimization with master to get skybox
Added maximum terrainRadius to sphere struct and caluculates it in Generateterrain
Merge commit '7b2b966bc9a11c725ca4009034fa70f7b592fd17'

Conflicts:
	controls.h
	planetsim.c