Synchronise 'Star' states into image files

[Webreaper]

Stars are stored in the .picasa.ini file on disk, and not in the tags within the photo. It would be much better to scan the .picasa.ini file and store stars as a tag within the image, and vice versa.

Whilst we're at it, we could also sync the other stuff in .picasa.ini into the image file - so that an image is self-contained. So we could have a tag for 'filters' which stores the last filter applied, and so on.