Start replacing OVR::Matrix operations in Scene with MatrixMath.h operations.
Extract OpenGL-style matrix parameter as float*.
Hoist the mview and persp float* decls near the parameter list.
Rephrase ceiling transform in MatrixMath functions.
Switch parameter from OVR::Matrix to float*.
Remove DrawGrid and _DrawWireframe functions.
Switch DrawScene parameters over to float*.
Remove all references to OVR SDK from Scene, rephrasing matrix operations in terms of the included utils.