Fixes#330
Also, fix incorrect patch application introduced by previous commit, it
would not read the patch color value, and could only switch the light
off.
Do not entangle brush model loading with loading surface lights.
Do a separate pass over brush model surfaces for the sole purpose of
finding light sources. Enables consistent live-reloading light data
after patching entities/surface/rad files.
this is not correct, but at least we get to see something
need to figure out how should blending work in rt:
- translucent materials that absorb light
- reflective+refractive
- etc