Bad casting recipe, no cookie.

When adding the casting recipes for metal tool parts, the liquid metal quantity is produced from the calculation `IPattern.getPatternCost(ItemStack) * ingotInMillibuckets / 2`. However, the ItemStack provided to getPatternCost is supposed to be an ItemStack containing the pattern (in this case, the cast), **not** an ItemStack containing the tool part.

Also, the name "metalCast" for what is obviously the actual output item (e.g. pickaxe head) is kind of silly. Let's fix that.