Game page form needs check for creating duplicate companies

Been looking through the newly created companies, and I'm seeing a lot of duplicates. Seems most, if not all, are the result of inexperienced wiki editors entering the same new company in both the developer and publisher fields when fleshing out a self-published game, thus creating two new company pages, one for either field.

It would be much better if you could assign both fields to the same new company, or at least get a warning that you're about to create a duplicate.

(BONUS BUG: I reported this several weeks ago, but the Damascus Gear: Tokyo Shisen game page still gives nothing but a 500: Internal Server Error when you try to access it.)

@blacklagoon: Thanks for the note, I'll file some bugs.