Housekeeping

Some general cleanup. Goals:
* Have tests passing out of the gate (provide .env.test)
* Remove unneeded files/folders/gems/routes
* Upgrade Ruby (2.1.5), Rails (4.1.8)
* Make Gemfile more readable

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AC & CT
I'll verify in the morning for sure, but I believe so.

In case it does not, what is the case for wanting to run the app without having Bugsnag configured? I would almost think having a explicit error thrown (`ENV.fetch`) would be preferred.  Having an app running without the ability to report errors seems like unwanted behavior.