Fix release_group detection for scene naming

[McBaws]

The release group isn't properly parsed from some files that use scene naming.

Example: {'file_name': 'JoJos.Bizarre.Adventure.2012.S02E47.Dios.World.3.1080p.BluRay.Remux.DTS-HD.MA2.1.H.264-Meakes.mkv', 'file_extension': 'mkv', 'video_term': 'H.264', 'video_resolution': '1080p', 'source': 'BluRay', 'release_information': 'Remux', 'anime_season': '02', 'episode_number': '47', 'anime_title': 'JoJos Bizarre Adventure 2012', 'episode_title': 'Dios World.3'}

This naming style has most of the information delimited by ., but the release group delimited at the very end by a dash. Ideally, anitopy would correctly return 'release_group':'Meakes'.