Changing the range fails

[ruisoftware]

Trying to change the current range properties,
$yourPlugin.rsSliderLens('option', 'range', { type: [ -20, 55 ], draggable: true })
does nothing, as a new range does not become visible.
After this, any mouse events causes further exceptions to be thrown.

[ruisoftware]

Besides fixing this issue, I've also greatly improved the jquery-rsSliderLens/src/demo/test.html.