Feature: Level Pools Enemies

[adonutwithsprinklez]

Add "levelPool" tag support to the enemy data type.

The "levelPool" tag should be able to modify (all of them optionally) the following tags:

• "HP"
• "damage"
• "modCount"
• "modifier"
• "weapon"
• "armor"
• "itemChance"
• "itemDrops"
• "xp"