Fix dealing too much AOE damage

Bandaid for #2170
Added McMMOPlayerVampirismEvent

Expands API possibilities regarding death penalty features.
Added McMMOPlayerPreDeathPenaltyEvent and McMMOPlayerStatLossEvent

McMMOPlayerPreDeathPenaltyEvent is fired before hardcore calculations
take place, use this if you want to cancel hardcore penalties.

Use McMMOPlayerVampirismEvent and McMMOPlayerStatLossEvent when you
want to know how many levels or experience the player lost or if you
want to modify this.
SHould fix #2195
This way is cleaner though.
Change purge a bit.  Apparently andrewkm says this works.
Move RefreshChunks setting from hidden.yml to config.yml

Adds #2213
Use provided instead of compile
Seperate pools for essential tasks like profile loading and profile saving.
Prevent players from having more than one database querying command running at once.
Use correct element
Added options to experience.yml for Dirt and Sand variations

Adds #2194
More relevant donation information
Add checks for loaded/unloaded profiles in commands
Use a placeholder value. Fixes #2216 #2221
Close the statement here as well
Added API to ExperienceAPI to get the amount of XP needed for a level
Cleanup the changelog
Should fix #2223 for realz this time.
Better connection validation for us.