new backdrop settings dialog

[Brian J. Tarricone]

Tuukka Mäkinen wrote:

> I think the screenshots look good. How does "random picture" work? Do 
> I give it a directory or a list of pictures? If the latter there 
> should be "New list" and "Edit list" buttons as in "Image list" mode.

at present, my idea was to pick a directory, and xfdesktop would pick a 
random image from the directory (i was also toying with the idea of 
having the image randomly changed after a specified timeout).  however, 
the "image list" infrastructure is already there, so it might make more 
sense to reuse that.  that way you can pick backdrops from different 
directories to put in the random rotation.

hmm... need to think about this a bit more.

    -brian