Bug where was using a dict for a list variable.
Updated partner seq local list test to handle maps' being references.  (Ie, call get_val on any reference before performing operation on it.)
When I changed maps and lists to be wrapped by references, where their
internal values pointed at InternalLockedLists and InternalLockedMaps,
I needed to also change them so that would try to incorporate deltas
and serialize their changes on their internal values.  This commit
creates a separate class for reference objects that passes along calls
to incorporating deltas and generating deltas to their internal values.