Mobs and ores only drop 1 experience orb

Summary

When killing most mobs, they should drop 1-3 or 1-2 experience orbs. This is no longer the case. A zombie, for example, now always drops 1 experience orb when killed rather than 1-3. Ores also now only drop 1 experience orb. All ores that drop experience should have a chance of dropping more than 1 experience orb, but they never do.

Steps to Reproduce:

1. Spawn several zombies.
2. Kill them.

Observed Results:

All of the zombies dropped only 1 experience orb.

Expected Results:

The zombies drop 1-3 experience orbs.