Patch for dragging photos to categories [Repost]

[Lee Willis <lee leewillis co uk>]

I created a patch to add support to allow you to simply drag a photo,
or photos to a tag and have them associated with the tag. The patch is
available online at:

http://cgi.lwillis.plus.com/p/dnd.patch

I originally posted it in May but didn't get any feedback. I'm posting
again now since there seems to have been some recent commit activity.

This is my first f-spot patch so I'm sure there'll be some comments on
the patch (Some bits didn't seem to work where I wanted them, so they
may be in odd places architecturally). I've also changed some of the
selection code in IconView.cs without significant knowledge about what I
was doing, however it seems to have fixed the problem I was experiencing
without breaking anything else. [You couldn't drag multiple items since
the button down event reset the selection]

It still applies cleanly, but I'll confess I haven't tested it with
a recent mono/gtk# build since I'm "sans broadband" right now to download
the latest releases

All comments welcome!

Lee