Change the classname vjs-control to vjs-button

[heff]

Originally 'control' was going to be the parent class of buttons and all other controls, but in practice only buttons use vjs-control. It would be a lot cleaner if we just vjs-button for button elements.

This would break existing skins so should wait for a major release. Though it's possible we could duplicate classes to help in the transition.

[gkatsev]

If you wanted to get this into a 4.x release, duplicate the names, otherwise, this is a pretty straightforward transition in a breaking API change release.

[mmcc]

We're going to break all the things when 5.0 drops.

[heff]

We discussed this a little on Friday, and the conclusion was that we need to switch to use the <button> element first, then decide what makes sense here classname wise. I think we should still have a vis-button class, and then decide if the vjs-control class is still necessary. It would be nice if the CSS class names matched the class inheritance.

[dmlap]

Decided to add vjs-button instead of removing vjs-control

[forbesjo]

Working on this.

[heff]

Closed by #2084!