Snow Particle Client Settings

[LevAlTru]

A copy of #122 because the branch got corrupted with unwanted commits.

• Players have the ability to choose snow particle behaviour on client side.
  • Default: no changes to the original snow particle code.
  • Box Collider: tries to reduce the CPU usage by making particles use a rough approximation of the train instead of making (a bit) expensive collision checks.
    • Might be an issue for custom maps.
  • No particles: removes client side snow spawn. If the snow is spawned via command, the behaviour is equal to default.