Merge pull request #2 from boskee/master

Updating #2
Merge pull request #3 from boskee/master

Updating #3
Merge pull request #4 from boskee/master

Updating #4
Issue #38 - File manager.py created. Repository reorganized. TODO create a file named defines.py, to change things like 'resources/images/textures.png' for '%s/textures.png' % images. TODO create other modes for update() in manager.py
Merge branch 'master' of git://github.com/embatbr/Minecraft
Players can't place blocks on top of blocks with density < 1 (eg. water).