Improve gui experience for large models (like Spaun)

[tcstewar]

Right now, it's pretty awkward to work with large models. This issue is just meant to brainstorm some possibilities of what we can do to improve things. Some initial ideas:

1. Multiple views (being able to save a GUI layout and quickly swap between layouts)

2. Adding graphs without rebuilding the model (this would require some support from nengo to add/remove things to a live model)

3. Speed improvements with large models (the interface can get slow and jerky)

4. Running just a subnetwork of the model with fixed inputs (or with inputs copied from a previous run)

Other ideas?

[jgosmann]

2. Adding graphs without rebuilding the model (this would require some support from nengo to add/remove things to a live model)

That could be related to having an incremental build process (nengo/nengo#869).

5. Panning the whole view when it's completely covered with a network (instead of moving that network). Maybe with a hot key, that would also make moving around in other circumstances easier as you don't need to find a visible spot of background to click on.