Moved seed creation from main.py to controllers, made it save
Also added G.SEED
Added TerrainGeneratorSimple, using (Simplex) Perlin Noise
Replaces the "flat dirt" with a flowing heightmap.
Should improve performance over the previous commit, as full-air sectors are no
longer continuously trying to regenerate themselves
Adds perlin.py from https://pypi.python.org/pypi/noise/