Version pre-alpha-140714a

===Additions===
-Inventory
    -Broken blocks are saved in inventory and used when placed
    -It can be visualized with E
-Placing of back blocks (like trees)
    -By clicking with right mouse button instead of left
===Modifications===
-Dinamic loading of blocks
    -Increases performance
-Zombies despawn faster
-New tree pattern
    -Trees look taller, but they have the same wood
-World saving disabled until #10 is fixed
===Fixes===
-#8
-Spritesheets being loaded every tick, causing lag