This updates Nengo Extras to be compatible with Nengo 3.0. Note that there are several tests failing, which I have not attempted to fix. This just allows Nengo Extras to be imported without error, so that the parts that do work can be used. Since we're not really actively maintaining Nengo Extras (and we may be significantly reworking it in the near future), it didn't seem worthwhile updating a bunch of legacy code at this point.
This updates Nengo Extras to be compatible with Nengo 3.0. Note that there are several tests failing, which I have not attempted to fix. This just allows Nengo Extras to be imported without error, so that the parts that do work can be used. Since we're not really actively maintaining Nengo Extras (and we may be significantly reworking it in the near future), it didn't seem worthwhile updating a bunch of legacy code at this point.