Added simultaneous downloads
Added automatic restarting (Force Failure, Requeue) of downloads when plex service is restarted.
Added Call to Function to restart downloads
Resolved simultaneous_downloads not following Pref['simultaneous_downloads']

Added function to inspect current queue's for zombie downloads.  Restarting as needed.

Added auto_force_success to auto force success of zombie items at 100

Calling Queue Check function, at startup, upon download refresh, and when Pref change.
Merge branch 'stable' into Multi-Download

Conflicts:
	Contents/Code/plex_bridge.py
	Contents/DefaultPrefs.json
Merge branch 'Multi-Download' into stable