Rename a common special case of getMetadata on Community and Collection.
This avoids collision with an identical signature which will be moving
to DSpaceObject, and avoids a lot of fixup code scattered all over.
Tidy up some hints
Move Context, TableRow to supertype, take more hints
Move common metadata operations and plumbing to DSpaceObject.
Disambiguate two more deviant getMetadata()s.
Move Item.ANY to DSpaceObject.ANY, comment on confusing nature of MetadataCache.
More documentation