* Changed "version" to "dataVersion" in data format
* Changed the "modName" and "modVersion" fields on the ModVersion
class to remove the "mod" prefix and changed the data format to
match
* Change the Stack class to use the itemSlug instead of the item
itself
* Update the ModVersion and ModPack classes to include methods for
recording a correspondence between slugs and names. Update code
which displays items from stacks to use these methods to determine
display names.
* Add a reference from Recipe back to the item it creates