WIP Don’t call the view general update method if just _view_count changes.

[jasongrout]

This may solve the issues we're having with _view_count changes in pythreejs causing infinite event trigger loops: jupyter-widgets/pythreejs#95

CC @maartenbreddels, @SylvainCorlay

[maartenbreddels]

Ok, if this solves it I'm ok with it. But I did get annoyed by all the websocket msg'es flying around, making debugging difficult. So do you think we should have an opt-in option, where by default it shouldn't keep track of the _view_count, but only when a new property (say _record_view_count ) is set to True?

[jasongrout]

But I did get annoyed by all the websocket msg'es flying around, making debugging difficult.

True, it doesn't solve that issue.

but only when a new property (say _record_view_count) is set to True?

I guess we get some weird semantics if the record attribute is set after views are created. Another thing we could do is to let _view_count be None, and if it is None (i.e., null), then don't update it.

[SylvainCorlay]

This looks good to me.