MV3: Intercept RIS, BibTeX on Google Scholar

[adomasven]

https://forums.zotero.org/discussion/115977/connector-does-not-send-citations-to-app

[dstillman]

Not that it should matter, but if I recall it's actually .enw (which is Refer/BibIX, I think) that people are importing from GS. The others don't set an appropriate Content-Type (though maybe we could support them anyway).