[WIP] Improve responsive resize handling

[tf]

• Ensure _handleResize callback is always defined, even if responsive prop is false initially. The callback might be needed if we want to add an event listener later on in componentWillReceiveProps.

• Use new refresh method to redraw the wavefrom and also update the play progress without actually seeking in the media file. There does not appear to be a need to pause while doing this. Wait for isReady, though, to prevent calling refresh before wavesurfer#init has been called in componentDidMount.

Once katspaugh/wavesurfer.js#1146 is merged and released, the peer dependency needs to be updated accordingly.

[tf]

Looks like responsiveness has been removed on the v2 branch and will be handled by wavesurfer itself in the future.