Moved model-like code out of manager.
Added parent/child API.
Throttling now occurs on a model by model level.
View/cell association is fixed for the most part, but there is still
one assumption being made in handle_com_msg.
this model does not work with the comm/widget communication model.
We need to be able to load the dependencies before we send the
show() message to the widget manager. Otherwise a race condition
will exist where the widget manager may recieve the show message
before the dependencies have been loaded (happened almost every time).
Jonathan Frederic