Start of 1.7.4 update

In a similar manor to my other recent pull requests this seems to work, but I have by no means tested the wide range of things humbug is supposed to do. Most of the difficulty in this came from changes to Minecraft's handling of entities and items. Mojang made it a lot easier to add custom items and a lot harder to make custom entities. Meaning the mess of Maps you may notice are necessary because they added test against overloading an existing class in the normal function to register Entities forcing me to create my own. On the good side they've made there item code a lot more flexible and in what I'm sure is very nice for our client side friends it is now incredibly easy to overload items and blocks, but this did mean some things had to change.  There were also some changes to the CombatTag api that required addressing.