Various fixes to camera and bounding volumes.

CC3Node createBoundingVolume only creates BV if one does not exist already.
Fix bounding volume display issues when primary node is tinted or faded.
Ensure BV when requesting it be drawn or intersections logged.
Add convenience debug logging of camera move...toShowAllOf... methods.
Remove mesh & material switching tests.
Add shouldBlendAtFullOpacity property to CC3Material and CC3Node.

Add shouldBlendAtFullOpacity property to CC3Material and CC3Node to help control
how changing the opacity of a material affects the blending properties.
Extract CGImageRef from rendered framebuffer.

Add CC3RenderSurface createCGImage and createCGImageFrom: methods to extract a
CGImageRef from a rendered surface. Add example of extracting and saving image
to file to CC3DemoMashUp.