Post'n'Stuff V4.2 - Godray Occlusion Fix

Changes:
- Godrays now depend on how much of the sun is actually revealed above terrain / the horizon.
- Mountains and horizon lines can now block or partially reveal the rays.
- Rays can spill in from the screen edge when the sun is just off-screen, instead of disappearing immediately.
- Godray defaults set to: strength 0.60, length 0.82, density 0.72, sunset boost 0.50.
