0002649: Eliminate slow dynamic_casts from front end render pass
Description
Some profiling in release builds shows that about 20-30% of the time in RenderHighlighted is spent on the boost::dynamic_pointer_casts. This should be easy to get rid of, as 99.99% of all nodes in a large scene are Renderables (except the root node) and many of them are selectables too.
Done. The frontend render pass is now taking less time than the backend, I could reduce frame times from 120 msec to 60-70 msec on my system when rendering the entire gathers map with cubic clipping switched off.
