Fixes: DLNA poster, Rating & MPAA Rating

DLNA poster:
    Get poster from movie_name.jpg (many DLNA servers/clients work this way)

Rating:
    Work with Ratings that have commas e.g. 8,6 (for countries that use comma as decimal symbol instead of dot)

MPAA Rating:
    Work for both "Rated bla" and "Rated bla blu" (the previous didn't work for "Rated bla")