New Feature - Exclude Skipped Albums In Total Artist Track Count

Added a new option to the configuration page called "Exclude Skipped
Albums In Total in Have Counts". When ticked, the total "Have" count for
an artist will only include albums marked as Downloaded or Wanted.

The totaltracks for the artist will not include skipped albums.

A "Force Update Active Artists" is required when the artist already
exists in the headphones database.

The Windows GitHub has screwed up my "Files Changed" so it looks crap from my end (was fine inside the client). Hopefully the merge will be ok though.