add event for finished execution of cell

[dkrenn]

closes #2060

At the moment, there are is no event that signals the completion of the evaluation/execution of a code cell (FYI, there is one, if the execution starts). The aim is to implement such an event.

[minrk]

Thanks, @dkrenn! Looks like this PR was made against the wrong branch. Can you update the base to :master? All PRs should be made against master, and we can consider backporting after merge if necessary.

[dkrenn]

@minrk Set to master. (Bckporting was not meant by me; simply I wanted to show only correct diff, i.e. the changes that I made branching from 4.3.1. Now the PR is crowed again...)

[takluyver]

I think you'll need to make the commits again starting from a recent commit on master (or copy them using git cherry-pick if you're comfortable doing that). Because you made the commits on top of the 4.x branch, targetting the PR to master doesn't work.

[dkrenn]

@takluyver Sure, this will work (even merging in master on my branch should work). However, there are (as far as I have checked) no merge conflicts at all, so a from a git-workflow-perspective, no need to do such a thing as merge master in or rebase it on master. Not sure, what Github's problem is with this.
Branch-update follows...

[dkrenn]

Ok, I see the problem now: Your master builds up on 4.1.0, whereas my branch builds up on 4.3.1. This explains now all the merging issues.

[takluyver]

We do 4.x (for instance) releases from master until we merge something which we only want to go into 5.0. At that point, we create a 4.x branch for further releases, and backport changes into it. In this case, that happened after 4.1.

[dkrenn]

@takluyver Thanks for the clarification. I cherry-picked now. Looks much better now :)

[takluyver]

Thanks. This looks OK to me now. We'll leave it a while for other people to take a look, and merge if there are no objections.