Kernels page reloads unnecessarily when switching language

[lgeiger]

[rgbkrk]

We should move much of the layout stuff to _app.js which we haven't taken advantage of since it originally launched.

[lgeiger]

I think this is mainly a problem of our custom server and the next.js router not playing well together.

I wonder if we should just rip out the custom express server and use queries for persisting the language selection. This would mean changing the URL from nteract.io/kernels/python to something like nteract.io/kernels?language=python.

[rgbkrk]

I think now that we don't do the redirect we can switch to a plain next setup.

[rgbkrk]

Oh also we can do the query thing and keep those paths with the custom server. It's what we do for commuter.