Java Edition Alpha v1.0.13

Alpha v1.0.13 is a version released to fix bugs and to work towards multiplayer.

Changes

 * Slimes have new look.
 * The client now checks if two instances of the game try to save to the same level, and quits if it does.
 * It is checked with a file.
 * Multiplayer progress.
 * The arm no longer gets stuck if is disabled while moving.

Fixes
1 bug fixed


 * Fixed a crash related to lighting.