colorpickersliders.destroy + colorpickersliders.reset events

I wanted to limit the number of  <code>div</code> created by the plugin, for http://imaguiraga.github.io/bootstrap-css-customizer/customizer.html site which uses controls  bound on clicks to a color picker. 

So I've added colorpickersliders.destroy + colorpickersliders.reset events 
to have a functionality similar to <code>"destroy" event</code> of http://bgrins.github.io/spectrum/

Please review this change
Thanks