Version 1.1 was just released.
It includes an editor for relations, removing the need to edit them externally.
Also now uses regular expressions to forbid invalid attribute names and gives to the user more feedback on incorrect relations.
For now windows and mac versions are not available, but the introduced support to PySide should make it easier on Mac to install the dependencies.
For the developers, the API has been changed and now accepts unicode objects instead of utf-8 encoded strings.