Basic support for nengo_spa.

[jgosmann]

This adds basic support for nengo_spa, but breaks support for nengo.spa (note the dot instead of underscore). There might still be things that do not work properly and before a merge the complete SPA related code needs to be gone through and checked.

I think there are slightly to many differences to conveniently support both SPA versions. With some refactoring this might be more realistic, but that also requires more effort and it migth be better to wait for the refactored frontend #806.

Ultimately, I expect these classes to move to nengo_spa, but this requires the plugin structure to be in place which I probably won't tackle before the frontend refactoring is done either.

[tcstewar]

Just before things go too far in this direction, I'm definitely going to make it a requirement that we will have to support nengo_spa and nengo.spa at the same time. It does make sense to have a branch like this for working with nengo_spa, but we'll have to support both before it gets merged.

[tcstewar]

(and, I think you're right that the eventual path to that involves the refactoring and then the plugin system, and then this ends up in nengo_spa rather than in nengo_gui)

[jgosmann]

Just before things go too far in this direction, I'm definitely going to make it a requirement that we will have to support nengo_spa and nengo.spa at the same time.

Yes, I'm on board with that. I just wanted to have an initial possibility to get the plots for nengo_spa. This is not intended to be merged in the current form (but the PR might make it easier to find if anyone needs it).

If nengo_spa provides the plots via a plugin system, the problem of supporting both should be solved because nengo_gui can still provide the code for legacy SPA without any changes and nengo_spa would provide the code that it needs itself.

[tcstewar]

This should definitely get merged, and it looks good to me. It'll get reworked when we connect nengo_spa and nengo_gui using the plugin system, but for now it's really useful to be able to use both nengo.spa and nengo_spa in the GUI. (Especially as we'd like to use nengo_spa in this year's summer school.