DBUS API BREAK: Model.Clone() now returns the last seen seqnum as second param. We need to do this because otherwise the receiver wouldn't know the seqnum of the clone contains 0 rows.
Bugfix: In of DeeProxyModel (and all subclasses, eg DeeSharedModel) the last seen seqnum was not always updated correctly
Bump version number to 0.3.0 because of DBUS API break