Java Edition 15w39c

15w39c was released to fix several bugs and improve performance.

Changes

 * Dispensers
 * Now equip pumpkins on the heads of players, mobs and armor stands.
 * Pumpkins still cannot be clicked to equip (intended behavior).
 * Performance
 * Redstone and piston contraptions visibly update much faster.
 * Better performance on older computers.