Improve gui experience for deep learning

[tcstewar]

Now that nengo is starting to support interesting deep learning (and reservoir computing) components, what can we do to improve the user interface side of these things?

This issue is just meant for brainstorming possibilities.

[Seanny123]

Worth revisiting later once we figure out how nengo_spa is going to work with the new Nengo GUI in a plugin-like way. Also, most of the interesting information about Deep Learning happens at build-time, whereas the Nengo GUI is focused on simulation time, so that's going to be an awkward challenge.