Adding PhysicalCraftingRecipe class

I created a PhysicalCraftingRecipe class for triggering actions when the user lays out blocks on the ground. It supports rectangular patterns, works in any horizontal orientation, and can identify item data values. The API is very similar to the Bukkit crafting recipe class. I've been using it in GiantTrees for a while now and it's pretty quick. I thought this would be a good addition to deshtutils.