Oauth upgrade

I cherry-picked a bunch of commits from @demental's repo that update the Omniauth and re-enable twitter as a login option.  I have not tested any oauth login methods outside of twitter as it's the only app I have an application associated with.

the APIClient libraries for twitter are still using the v1 API which twitter no longer supports.  I've disabled the parts of the twitter search so it doesn't return any obvious 500 errors.  Again, not sure about other APIs.  WIll need to get this on a publicly accessible server to test other auth and search methods.

Some acceptance tests are failing due to img.logo matching errors, but the pages associated with the errors look okay.  Anyway, WIP, but probably better that what we have on production now.