NzbDrone support

Although NzbDrone says that a post processing script isn't strictly needed, I've had it attempt to move downloads before they've finished unpacking. So I decided to add NzbDrone support to nzbToMedia!

This has been tested by myself, and seems to work just fine. I have a pretty simple setup though, so any other testing would be appreciated.

 - Added nzbToNzbDrone script, as well as added NzbDrone support to nzbToMedia.
 - Rather than adding to autoProcessTV, I created another script, autoProcessTVND (I know, original name...). This does lead to some code duplication, and fixes for one will have to be added to the other too, but I thought this was cleaner than throwing a bunch of conditionals into autoProcessTV. If that's wrong, let me know and I'll make the changes...
 - Added default config to the main .cfg.sample file and migrate code for NZBGet.
 - By default, the same category as SB is used, but SB is preferred as it is checked first. An option also exists to prefer NzbDrone if there's a clash.
 - NzbDrone needs an API key; basic auth is being removed soon.
 - I didn't include the delay options that SB uses, as NzbDrone returns immediately from the API call; it doesn't wait until the end, so there's no need to include a timeout or delay. It might be possible to check the status of the scan, but I don't think that functionality exists yet.