upnpsoap: correctly terminate SamsungGetFeatureList Features

see http://sourceforge.net/p/minidlna/bugs/210/

Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
albumart: search for .tbn rather than .jpg album art

The is really only to be compliant with a shared xbmc and minidlna
directory.

Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>