Issue Description: Tried with both releases 2.2.3 and 2.2.5. The soul shard gets identified as wither skeleton soul shard when a wither skeleton is killed, then all subsequent kills of the same type do not increase the kill count of the soul shard. Tried with and without the soul looting thing enchantment.

What happens: Soul shard number count does not increase

What you expected to happen: The soul shard count to increase

Steps to reproduce:

1. Have any empty soul shard in hot-bar
2. Equip weapon of choice
3. (Assuming in nether fortress) put down skeleton spawner
4. Kill wither skeleton once for soul shard identifier, then 2nd tome to observe bug.
5. ???
6. Obtain bug.

Affected Versions (Do not use "latest"):

• Soul Shards: 2.2.3 and 2.2.5
• Minecraft: 1.8.9
• Forge: 11.15.1.1764

Should be available on Curse shortly. Otherwise, here.