Renamed DataRecord -> DataRecord, moved to datamodel.record package
Removed unused HashCode/HashCode interfaces

We won't be able to use hashes for version identity as some clients will not have permission to view
all fields on an instance and so will receive a different hash value.

I think we will need something closer to vector dot clocks for version numbers.
Removed SerXX classes, to be replaced by Record interface
Replaced SelfKeyProvider with gwt-provided SimpleKeyProvider
Started to integrate Record model and FormClasses

(Small Step) Replaced core.shared.Cuid with datamodel.shared.Cuid