Travis and test fixes

I fixed failing tests by switching Resque mentions to Sidekiq; they are now green, but I don't know too much about Sidekiq so you may want to check those edits over. I also got Travis-CI working (on 1.9.3 and 2.0.0 at least, it fails on 1.9.2), but you need to apply my last pull request as well, in order to fix a moved gem.