When moving a UIFileGroup around the Diagram, make sure we only check
the (x, y) coordinates relative to the Diagram, not relative to any
other objects we might be passing over.
- Implement IPackageMemberMgr.getNeighboursOf() method for determine the
left/right neighbours of a file group, or of a package instance.
- Convert the SlotMgr.* methods that currently use in-memory data
structures so they now use database tables.
- There is still work required to fully implement the SlotMgr.* methods,
especially for error checking.
Add error checking for SlotMgr methods, as well as copious unit tests.
- Implement and test setting/getting of slot values.
- Implement SlotMgr.isSlotSet() and SlotMgr.clearSlotValue() methods.