Axis invisible with margin 0

[SinBirb]

In horizontal orientation, when specifying margin(0), the axis is not visible.

Workaround is to remove the height assignment in line 104 (https://github.com/turban/d3.slider/blob/master/d3.slider.js#L104):

svg.attr({
    width: sliderLength + margin * 2
    //height: margin
});