fixed volume for youtube html5 [Delivers #76987952]

This does not look right. Why are you setting ```_ytPlayer.volume``` AND calling ```_ytPlayer.setVolume(_lastVolume)``` after?

Also ```.volume ``` gets a value between 0-1 and ```.setVolume()``` a value between 0-100. That can't be right.

@emaxsau, y are not using _ytPlayer according to Youtube's spec. There is no .volume property, and I think they expect volume to be set to number between 0 and 1 not 1 and 100.