Updated for 1.6.4, Bug fixes and more

- Updated for Bukkit 1.6.4. At the moment Corruption still relies on
some of the Deprecated Magic Values functions. Added TODO tags for
deprecated functions to which no direct alternative exists.
To update without reducing features, we now use
com.mcdr.corruption.util.legacy.ItemNames and .EnchNames to store the
'old' ItemIds and EnchantmentIds.
- Fixed a bug where mobs with a health multiplier would increase in
health every time they were reloaded
- Fixed ability activation chance. Prior to this, the activationChance
would be ignored due to sloppy coding.
- Fixed a possible bug with the CorruptionAPI.isBoss(Entity e) method.
If the getBoss(e) returns null, there's no use in looking any further.