Added SlotBrewing for diff visibility
Added PotionBrewer for diff visibility
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 PotionRecipes as a class to store the different overrides and recipes. Added CraftBrewRecipe to CraftServer's addRecipe method.