Provide determinant accessor in render state structure.

Provide determinant accessor in render state structure.

This allows custom renderers to set the determinant to a value
different than the actual model view transform matrix. This is
useful when parts of the scene node transformation are done on
the CPU rather than in the vertex shader.

Change-Id: Icf26a5922b0933275a61af4656cf842bf61e70d5
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>