Some extension now need events

[Carreau]

in particular SWC and init_cell need to be passed "base/js/events" and the call to register_preset updated. assigning me.

[juhasch]

Basically we now have three generations of nb extensions.

• 1.x
• 2.x + 3.x before require.js,
• 3.x after require.js
  OK, we don't need to care too much for 1.x anymore I think, so only two.

Do you have a suggestion how to handle the different versions ?
We at least need to update the descriptions, have different custom.js examples and some extensions will need to be updated. Simply ignore anything before require.js was merged and only caring for the new stuff seems pretty drastic.

[damianavila]

We need to provide at least support for before and after require.js, I agree that 1.x is getting old quickly, and it will be more quickly as long as the 3x and 4x see the light...

[Carreau]

There are still some fixes on their way for 3.0 that would make most extension of 2.0 work with 3.0.
We will do a compatibility layer (at least for notebooks formats) on 2.x, so I guess we can add soem shim on 2.x that simplify the sharing of extensions between 2.x and 3.x

[damianavila]

Seems reasonable...

[juhasch]

Sounds good. I'll look at the other extensions in usability, once ipython/ipython#6119 is merged.

[juhasch]

I think we can close this now. All active notebook extensions for 3.x have been updated or do not work anymore anyway.