initial commit of work on generic JSON<->Things API,

This will provide a way to easily swap between "native" (via bukkit's
restrictive UnsafeValues "API"), "Utils" (a reimplementation of the
parsing built atop other parts of Bukkit's API) implementations of a
JSON<->Things API to transform ItemStacks, entities and such to and from
JSON.
Fix imports
Add UUIDFetcher, Add static sqlTags