make unique mutex for each install location. Fixes #567
mutex can't contain "\". Fixes #567 #545
don't fail if option already deleted above. Fixes #571
check for CHD in NZBDrone and return. Fixes #485, Fixes #572, Fixes #568
if corrupt vids, set status failed for NDrone CHD.
remove procin terminate. Fixes #568
don't clean before Drone processes. Fixes #568