Still making it optional, but this seems to go pretty fast.

Routines under the Examples tree that start with “rtbMake” are treated as callable examples in various test programs, so we don’t want helper functions to start with rtbMake, at least if they are under the Examples tree.

And save a png image out in any case.

This reverts commit 1765396f.

Cleaned up example scenes for Crytek, Sponza, and OpacityAndBumpTest. Added chess set example scene to show off metadata abilities.