Java Edition 15w40a

15w40a is a snapshot that changed mob ai and health regenaration.

Changes

 * Mobs
 * Changes to mob pathfinding.
 * Mobs now avoid cacti and fire.
 * Blazes won't avoid fire.
 * Passive mobs following a player holding food will now go around water, if possible.
 * Entities panicking and on fire will preferentially run towards water within ±5 blocks horizontally and ±4 blocks vertically, even if they can't actually reach it.
 * Shulkers
 * No longer attack in peaceful difficulty.
 * Shulker bullets despawn in peaceful, but not shulkers themselves.
 * Health
 * Health regenerates every half-second instead of  every 4 seconds, when saturation is not empty.
 * Regenerating health increases exhaustion by 4 points rather than 3.