Initial work toward restoring snow particle system
Fixed issue where particle system (snow) was functional but not being
rendered; updated snow particle system genration logic; fixed issue with
seeding the random number generator in the lua script's update function
(which ensured that calls to rand() would ALWAYS return the same value).
Remove unused variable/function from development of snow particle system
featrue.
Merge pull request #1 from srobbibaro/snow-particle-system