requested: dirt blocks under grass for generation

See line 259.  that is all that you need.
Requested: Dirt blocks under grass for terrain

see line 259
Revert "requested: dirt blocks under grass for generation"

This reverts commit 4a1bf3328b038da6ae8c8aa54df4e6d92baf358c.
fix: dirt blocks under grass for generation

See main.py, line 259, that is all that you need.  Also, updated to
other's commits.
block checking, better dirt under grass

not perfect, but it works.  some grass on grass overlap may happen.
dirt under snow blocks

forgot about dirt under snow, fixed.
Merge branch 'master' of git://github.com/ronmurphy/Minecraft