new: repeat button for Play widget, can be hidden

[maartenbreddels]

As discussed in #1186 this adds a repeat button. I've chosed the fa-retweet button, since the fa-repeat does not look like a repeat button.
Futhermore I've included what I think is a fix for Play, it now includes max, since that is more consistent with the slider's max behavious.

import ipywidgets
p = ipywidgets.Play(min=0, max=3, interval=500, show_repeat=True)
s = ipywidgets.IntSlider(min=p.min, max=p.max, value=p.value)
ipywidgets.jslink((p, 'value'), (s, 'value'))
ipywidgets.HBox([p, s])

hide repeat button, and turn on repeat:

p.show_repeat = False
p._repeat = True

[SylvainCorlay]

Awesome!

[maartenbreddels]

Futhermore I've included what I think is a fix for Play, it now includes max, since that is more consistent with the slider's max behavious.

Is it an idea to take this in a seperate PR, since it will be nice to have this consistent for 7.0, and leave the extra button for 7.x or higher.
Since now Play goes from min to max-1, while a slider goes from min to max (inclusive), having this consistent makes sense.

[jasongrout]

I think either way (fixing the consistency issue, or also including the new button) is fine for 7.0.

[maartenbreddels]

So, do you mind if I merge this then, I've tested it myself. Should the change in behaviour of Play go in some changelog?

[jasongrout]

Can we only reset it to the min if we are repeating? Reverting to the min after a straight play through has been frustrating to me, instead of just stopping at the end and freezing the state there.

[maartenbreddels]

I agree!

[jasongrout]

Yes, there is a changelog at https://github.com/jupyter-widgets/ipywidgets/blob/master/docs/source/changelog.md

[maartenbreddels]

$#@% messed up rebasing, any idea what I did? :)

[jasongrout]

Looks like you figured it out.

I don't see that I can 'approve' sth

[maartenbreddels]

Yes, I had to git push --force ...
Sorry I had to dismiss your review :), but I didn't see any other option.