Blender Git Loki

Viewport: Fix stereo 3d camera framings when pivot is not center

As reported by Cl�ment Foucault. This is a small thing but since we
are refactoring the draw manager for the next blender is nice to
have it fully working before the refactor for comparison.

Note: Camera volume and render were both fine, the camera frame is the
one thing that was not working.

Also in toe-in the convergence plane is always facing the original
camera orientation. It is a known small annoyance.