MacGui: When reloading a previous queue at launch, as well as pending encodes also...

MacGui: When reloading a previous queue at launch,  as well as pending encodes also reload a queue item marked previously as "encoding" if it exists.
- An item marked as encoding in the qeueu at launch  indicates that either we crashed during that encode, or that the user shut down during that encode.
- If the user chooses to reload, we change the status back to pending. Note: the encode will be at the top of the queue after launch.
- Change the queue reload alert window to tell the user how many pending jobs they have as well as if there was an encoding job.

git-svn-id: svn://localhost/HandBrake/trunk@1745 b64f7644-9d1e-0410-96f1-a4d463321fa5