Cleans up the Field interface
Cleans up the Field interface

Remove the requirement for setting the primary key flag at the field
level.  The containing DBTable already has this information.

Change the get/set UDT name methods.  PostgreSQL is a little odd here
in that all types are User Defined Types, where other engines don't
see things that way.  Just going to call them "defined types" for the
purposes of describing a field.

Metrol/dbtable