Added LavaParticles.cs
- World is now done in fake 3D and more obviously in the middle of some
  lava
- Little particles now shoot out of the lava periodically; This is
  incomplete-ish, I want to see how little sparks coming off the sparks
  look
- Need to add a small wall in the background so the lava doesn't
  obviously disappear into nothing as pits go by