MacGui: Initial implementation of new queue sync code which allows multi-instance...

MacGui: Initial implementation of new queue sync code which allows multi-instance encoding.
This allows more than one instances of HandBrake.app to run off of the same queue file.
In the case of multi-instance use these changes occur in the queue window:
- The delete icon for a given queue item does not exist in the queue window if another instance is doing the encoding.
- The encoding icon does not spin if another instance is doing the encoding.
- As before if the queue window is for the instance doing the encoding on that item it will be animated and "spins".
- The queue window  status readout now also includes the output file name for the file being encoded for that instance.

Known bugs:
- Drag and Drop queue reordering is somwehat borked. Doesn't corrupt queue but can not allow a drop in some instances.
- I have tested this over 20 multi instance encodes and not once had an issue, but anytime more than one instance is writing to the same external file anything can happen. Beware!
- The session activity log will of course be full of activity log info from all instances in a multi instance scenario. Individual encode logs are unaffected.

git-svn-id: svn://localhost/HandBrake/trunk@3443 b64f7644-9d1e-0410-96f1-a4d463321fa5