* Decrement references for results of PySequence_GetItem. There were a few
places we were not decrementing the Python reference, leaking the value.
* Add tracking of Python arguments with recursive marshaling cleanup. This
allows arrays of GValues which have been coerced from Python types to be
properly free'd (also fixes bug 703662).
* Use g_variant_ref for variant arguments marked as transfer everything.
This fixes double free's caused by the decrementing of PySequence_GetItem
results.

https://bugzilla.gnome.org/show_bug.cgi?id=693402