Make flash embedding work much better...

- Make sure to give distinct callback objects distinct IDs, so they talk to the proper KHTMLPart. Fixes only one flash object working per window
- Rework the size/init heuristics yet again, following closer to Seli's code, but instead of trying to count events, etc., just have the part tell us when we were really resized, and qwidget isn't making up a randomsize.