Alpha 007a - Tree/Crafting Update

Changes:

+Added trees

+Added wood

+Added wood walls

+Added saplings

*Changed doors to wood doors


Bug fixes:

Fixed zombies vibrating at sonic speed back and forth if they were on a floor above you or below you

Fixed inventory slots being 1 pixel too big causing misalignment

Fixed the ability to shut doors while inside of them, trapping you

Fixed crash when walking off the right side of the world

Fixed being able to walk off the right side of the world

Fixed doors appearing closed but actually being open when placed