Cleanup overzealous new and init implementations

Remove PyGObject initializer code attempting to set properties on
GObjects that have already been created. There were a number of
overridden __new__ and __init__ methods that stripped away
arguments before calling the base class to work around attempted
property sets and argument count errors (fixing the symptom not
the problem).
Use Gtk.ListStore/TreeStore.new with __new__ override instead
of __init__ with set_column_types.

https://bugzilla.gnome.org/show_bug.cgi?id=705810