Add Plex parsing rules for TV Shows.

Allow for reading the TV show title from the directory name. The idea here is to match Plex naming rules ( see https://plexapp.zendesk.com/hc/en-us/articles/200220687-Naming-Series-Based-TV-Shows) so that the user can have `/path to/TV Shows/Show Name/Season N/S03E01-E03.mp4` and have the parser determine `Show Name` and episode 1.

 - Fix the regexes that match to Plex rules
 - invert the order of `$file, $directory` to match previous usage
 - unit test.