further implement morphia DAO

allow morphia to store className with document so that interface
resolution can take place
Add @Transient objectid to MorphiaPerson for database management
simplify PersonDAO. It's assumed that a document that needs to be
published or saved as Draft originated in the database and has a valid
ObjectID. This keeps ID management separate from the interface.
There's still an issue with morphia returend ojects not being @Injected
by guice
http://stackoverflow.com/questions/16593423/guice-doesnt-inject-morphia-returned-object
missed this file in last commit
remove need for injecting into VersionedPerson