Add inventory visualization (WIP)
Modify inventory visualization: now has a backgound and is centered
Modify inventory: items are used whem placed
Modify zombie despawn: now it's faster
Modify loading of blocks: they are no longer loaded every tick, performance increased
Fix issue with item selection
Fix issues with world loading
Fix issue with respawn and chunk loading
Modify spritesheet loading, HUGELY increasing performance
Fix more issues with world loading
Modify tree pattern
Modify tree pattern (again)
Add placing of back blocks
Fix #8
Fix trees overwritting grass
Disable world saving/loading until issue #10 is fixed
Update CHANGES and README for pull request
Merge pull request #11 from SuperF22/development

Version pre-alpha-140714a