profiling has shown that a lot of time is spent in the
mapper setting the lighting uniforms when there are a
large number of mappers. In a more traidiotnal program
this is handled by a UBO or similar set once per program.
This topic addds in capability to the shader program
to store an mtime associated with a group of uniforms.
It also makes use of that capability by having the renderer
generate shader code for the lights, and update the unifoms
when requested and needed. The result is a significant reduction
in the time spect updating the lights when faced with many mappers.

This topic also includes a new benchmark to test the performance
of many actors.

This topic also includes a performance fix to short circuit
the mtime check for RenderPasses in the mapper. The most common
case is none and yet that case was taking significant time.