Spinny updates

* Add separate bg and mask paths to spinny -- the cover art goes between them
* Use pixmaps instead of images for scalable drawing
* Update LateNight with SVG spinnies

This doesn't work right -- the spinnies are drawing aliased even though the hint says antialiased.  I copied the drawing code from wknobcomposed so I'm not sure why it looks bad
For backwards compatibility the background should default to fixed and the setFixedSize call should be there if fixed (like the other widgets that have this logic).