Potential Memoryleak

[oweitman]

https://github.com/ioBroker/ioBroker.template/blob/9ab757f8f72d429c38bf9ea33529d83260073ca4/JavaScriptVIS/widgets/template/js/template.js#L47

If the widget is recreated or redrawn by vis the previous bounds are not automaticly deleted by vis/canJS and leads to a memory leak
redraw/recreation is triggered for example if you use binding.
the bound states should manually unbound with the unbind command or should
added to the data('bound') property of the widget. data('bindHandler') should also set
example: iframe widget of the basic set https://github.com/ioBroker/ioBroker.vis/blob/2a08ee6da626a65b9d0b42b8679563e74272bfc6/www/widgets/basic.html#L380