VersionSavers and Replayers can return enum constructors for replay.
Modified enum factory to return an atomic enum variable --- simplifies deserialization later.
Should deserialize atomic enums.
Added messsage to log deltas on enums.  Still need to build
surrounding version helper infrastructure.
Want to log changes to enums.  To do so, need special logic to serialize the enum.  Each enum will need a singleton version helper.  That version helper will need a serializer.  This commit provides the serializer for the version helper.
Expanded enumconstructor so that it generates enums directly, not just wrapped enums.  Will be useful when deserializing.
All enum objects now emitted with a version helper.
No longer permitting empty enums.  FIXME: should add code to type checker to ensure that cannot have empty enum.
Had not been initializing enum variables passed in arguments correctly.  This caused a test to fail.  Fixed.