Delete related files

When ND replaces an episode with a PROPER, it should delete any related files (subtitle, image) with the same name, not just the replaced mediafile.
This should also apply when ND has a higher cutoff and gets a better quality of an episode.

Currently NzbDrone v2 does not create or manage metadata. This is something we will be adding at which time it will manage metadata on upgrades.

OK, looking forward to it!