Add rendering option to enable/disable geometry scissors cache

Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>
Fix bug in SIMD implementation of UpdateWithWorldSpaceBoundingHull

Fix bug in SIMD implementation of sreScissors::
UpdateWithWorldSpaceBoundingHull. This resolves shadow errors
when geometry scissors are enabled.

Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>