'Return the first friendly_tag matching genre.
Scan self.genre_tags_dict[] for first friendly_tag matching genre.
genre_tags_dict[] populated in filter_genre_tags().
Args:
genre (str): genre to match
Return:
friendly_tag (str): friendly_tag matching genre'

def get_friendly_genre_tag(self, genre):

    for friendly_tag in self.genre_tags_dict:
        if (self.genre_tags_dict[friendly_tag] == genre):
            return friendly_tag
