Added contributors.
* configure.ac:
Bump gst core requirement to 0.10.8 for proper GstQueue behaviour
* pitivi/discoverer.py:
Handle gracefully more cases using no-more-pads information.
Remove hack for GstQueue mis-behaviour in pre-0.10.8 GStreamer.
Remove queues used when doing video thumbnailing (it only needs one
frame anyway).
Sprinkle a little more debug


git-svn-id: svn+ssh://svn.gnome.org/svn/pitivi/trunk@825 d3729300-e425-0410-8a4c-d956edccc248