Fixes for Python method descriptors
The method descriptors for VTK classes were being created before their type object was readied via PyType_Ready(). This didn't cause problems for most uses, since Python would do this itself at some point.
However, it caused ipython's tab completions to fail, because jedi (the tab-completion back-end) would attempt to get the mro of the method descriptors before it had been created.
Edited by David Gobbi