[cogl matrix] Support ortho and perspective projections.

[cogl matrix] Support ortho and perspective projections.

This adds cogl_matrix api for multiplying matrices either by a perspective
or ortho projective transform.  The internal matrix stack and current-matrix
APIs also have corresponding support added.

New public API:
cogl_matrix_perspective
cogl_matrix_ortho
cogl_ortho
cogl_set_modelview_matrix
cogl_set_projection_matrix