Fixed result content for Season Pack results

Added an extra check into the snatchEpisode method
so that the result.content data for a required
torrent is always downloaded if needed
Renamed bestSeasonNZB to bestSeasonResult

bestSeasonNZB is confusing in this context
we are dealing with results which can be
NZBs or Torrents
Merge pull request #743 from garvinob/branch-fix_torrent_seasonpack_downloads

Fixed result content for Season Pack results