Sun Kill PigZombies

• Fixed issue where this plugin stopped Monster Apocalypse from spawning mobs.
• Fixed performance issue
• Saves dmgPerTick setting

In-depth changes: Instead of looping through all Entities each second looking for PigZombies, I've rewritten this to keep an ArrayList of PigZombies, and loop through the list every second instead. When an Entity spawns I capture it via onCreatureSpawn and if it's a PigZombie I add it the the ArrayList. Also 2.5 seconds after a PlayerJoins I loop through all Entities and add any PigZombies.