Better bàb management and add "playInstruction" in tjhe js api.
{{! template for the slider widget - it's composed of two divs we one overlayed on top
of the other }}
<div class='Ldt-sliderBackground'></div>
<div class='Ldt-sliderForeground'></div>
<div class='Ldt-sliderPositionMarker Ldt-TraceMe'></div>