Allow dragging on picker and slider

[grubshka]

It should be quite easy and user-friendly to allow dragging on the picker and the slider, listening to "mousedown" and "mousemove" instead of click.

[sroussey]

This works on Chrome, but not Firefox.

[malihu]

A quick fix for firefox:

$(document).bind("dragstart",function(e){
    if(e.target.nodeName.toUpperCase()=="RECT"){
        return false;
    }
});