Fix non-english searches & return more info

I improved get_matching_shows() to take both a language arg and a want_raw arg.

The former allows someone to request language='all' (which is what I'm now using) or something like language='en'.  I made the default be to not add a language to the URL since a search w/o a language arg behaves differently than one with "language=en".  If you feel differently, you might want to change the code to substitute self.language for a None value and always include language in the GET.

I also added a want_raw=False arg since I need more search info than the default fields.  When called with want_raw=True it returns the raw attr dict.  I didn't make this depend on self.want_raw, since I figured show & episode raw-ness wasn't quite the same thing as search raw-ness.

One final tweak: I noticed in thetvdb wiki that they actually deprecated the mirror selection API, so I tweaked the comment that talks about skipping the API call to mention that.