Item dictionary

This works like the ore dictionary, but only one item (or block) will be created for each name.
For example, if 5 mods register "ingotCopper", only one of them will be called upon to create the item for ingotCopper. A config file can be used to select which mod's copper is used - by default it's the first alphabetically.

If you are using, say, Forestry copper, and you remove Forestry, it will automatically switch to a different type of copper and keep the same ID.