Pumpkin Tree/1.5 Update

Updated the code for Minecraft 1.5 (liking and hating the weird new way
to do textures all at once). Use bonemeal on a pumpkin to generate a
pumpkin tree! I don't actually want a pumpkin tree to be grown with
bonemeal, I just used it as a test. It would be cool if it could
generate in the nether though, or in its own Halloween-based dimension.