Kill capybara webkit with fire

I just had a terrible day attempting to fix my broken development environment, and capybara-webkit is mostly to blame. We're stuck right now between a Ruby version that's too low, and a QT/Webkit version that's too high in Ubuntu's package manager (not sure about OS X). So what that means is that when I removed RVM today, it became practically impossible to get a working build.

To explore other options, I tried getting us up to both the latest capybara/capybara-webkit versions. This is promising, but involves some breaking changes because a) it requires 1.9.3+ and b) it removes wait_until(). Both of these issues can be worked around, but they're not trivial, and the latter is made harder by the fact that our payment testing code is pretty brittle.

Here's what I'm suggesting: we kill capybara-webkit with fire for now, and then think more carefully about how to do proper javascript testing. The impact is that we're going to lose our stripe testing for now, plus the tiny sharing test we have. But I think maybe both of those areas could be tested in Jasmine or something else that would keep this massive dependency out of our hair, and it'd pave an upgrade path forward that's a little bit more simple.

I know this is a Catch-22 situation, but what do you think, @jordanbyron?