Enchancement bubble subview events

[RickButler]

I would like to propose an enhancement that I will develop to provide opt-in event bubbling for sub-views.
This gives event bubbling for sub-views, something which i know has been asked for before, with an opt in strategy so the we don't end up with adverse impact from listening to too many events.

subview: {
  mysubView: {
    bubbleEvents: 'change:render change:myValue',
    prepareview: function (el) {
      return new View({ el: el});
    }
  }
}

subview: {
  mysubView: {
    bubbleEvents: true, // or 'all'
    prepareview: function (el) {
      return new View({ el: el});
    }
  }
}

It will probably add a conditional call to
this.listenTo(subview, subview.bubbleEvents, this._getCachedEventBubblingHandler(subview));
inside _parseSubview, and may need some logic inside _parseSubviewOpts to turn truthy values into 'all'.