Java Edition 1.9-pre2

1.9-pre2 is the second pre-release for 1.9.

Changes

 * Spawning
 * Pack spawning is less likely to spawn the full pack, and less likely to spread them out.
 * Previously, spawning a pack would start from the center three times and cumulatively adjust the coordinates four times by up to ±5 in X and Z, trying to spawn a mob each time, for a total of twelve spawn attempts (although it stops early if a full pack has spawned). Now that "four times" is a random number 1–4, meaning fewer total spawn attempts and less chance for the attempt coordinates to get far from the pack center.