Turn the app into a mountable Rails engine

I've encapsulated our application as a Rails engine.  It looks like a big change, but actually everything is functionally the same.  The major change is that you'll now access the engine's routes using:

    /qa/terms

And I've also used Qa as the module namespace instead of QuestioningAuthorities because it was getting too long to type!

Take a look at the README for instructions on usage and integration with existing Rails apps.