album art: the corrects picture URLs begin with "file://" else, we have to download/extract/look in the cache
sets the ArtworkURL to the file in cache also when it had been extracted previously

\\\\ will become \ and \\\" will become "

Should fix problems with building libvlc.so.1 when libvlc.so.0 is installed.
Cannot test since the tree is currently broken.

The last song in playlist was not being submitted, since the current input would never change.

upnp intel: reverts [22521] to make it compile. The module should be rewritten to not use any playlist code