Updated list serialiation test to serialize tvar list.  It fails.  Must fix.
Forgot to remove assert from tvar list serializatin call.
When deserializing Atomic objects, require having a uuid (eg., to
determine whether had already encountered object before).  Note that
we're guaranteed that when a deserialization event is running, no
other event will touch the same object.  Therefore, it's okay to just
use a constant value for each deserialization event's uuid.