made the listWidget redraw at every timeupdate event (added a small optimization though,
to make sure that the widget isn't redrawn all the time).
{{! template for the slice widget }}
<div class='Ldt-sliceWidget'>
{{! the whole bar }}
<div class='Ldt-sliceBackground'></div>
<div class='Ldt-sliceLeftHandle'></div>
{{! the zone which represents our slice }}
<div class='Ldt-sliceZone'></div>
<div class='Ldt-sliceRightHandle'></div>
</div>