Grass now grows under up-side-down slabs
Remove old function
Merge branch 'master' into Slabs

Conflicts:
	src/Blocks/BlockDirt.h
Add CanChangeDirtToGrass function to Block Handlers.
Merge branch 'master' into Slabs
Remove old import
Merge branch 'master' into Slabs
Rename CanChangeDirtToGrass to CanDirtGrowGrass
Add lava and water check to block handlers.
Superfluous method override.
Merge pull request #853 from Howaner/Slabs

Grass now grows under up-side-down slabs