Added DO_ALL flag, setting to true runs epic scene test, while leaving at false does just three example scenes.
Added DO_ALL flag, setting to true runs epic scene test, while leaving at false does just three example scenes.

Signed-off-by: David Brainard <7bf71e13ed533be24d7a9ab04d98b2cedddd3384@psych.upenn.edu>

RenderToolbox3/RenderToolbox3,tlian7/RenderToolbox3,tlian7/RenderToolbox3,RenderToolbox3/RenderToolbox3,tlian7/RenderToolbox3,tlian7/RenderToolbox3,RenderToolbox3/RenderToolbox3,RenderToolbox3/RenderToolbox3