Added BrewRecipe and BrewEndEvent. Added PotionBitSet as a wrapper around the NMS string bit modifiers. Fixes Bukkit-2441 and BUKKIT-1604. Modified TileEntityBrewing and SlotBrewing to allow for new potion ingredients. Also modified PotionBrewer to allow the overriding of the potion's effects based on damage value. Added CraftBrewRecipe to CraftServer's addRecipe method.