+Khaled,Werner

Two things:

  * Werner, please please please remove code that change face->face_index.  It's bad bad bad.

  * With Matthias's branch, we break Khaled's code, ie. if user creates FT_Face, sets variations on it, and creates cairo_face_t from, we reset / ignore those variations.  The fix would require savings the variations that were on the face when face was created, and use those instead of instance-defaults in apply_variations().  Matthias, any chance you can do this?