Reorder ovecmath.c functions for easier navigation.

  This change puts the "fast" callable C version, when available just
before the definition of the wrapper called by the jit code.
Implement ortho, frustum and perspective simple matrix operations
Implement project, unProject, pickMatrix and lookAt helpers

  These use prototypes matching glu (with the exception that in a
few calls there is a matrix first argument) instead of matching glm
interfaces.