LinGui: allow multiple instances of the gui to run
Each instance has a queue named "queue.<pid>". On startup, the gui
opens and locks with lockf a file "ghb.pid.<pid>". Then it searches
for any other ghb.pid.<pid> files that exist that are not locked. If
it finds one, then some instance of ghb exited and may have left behind
a queue. Try to reload it. If there are no items in the queue, continue
looking for unlocked ghb.pid.<pid> files.
git-svn-id: svn://localhost/HandBrake/trunk@3212
b64f7644-9d1e-0410-96f1-
a4d463321fa5