    element.position(x, y, [opt])

Set the element position to `x` and `y` coordinates. This is almost equivalent to `element.set('position', { x: x, y: y }, opt)`. However, this method provides some additional functionality. If you set `opt.parentRelative` flag to `true`, the `x` and `y` coordinates will be treated relatively to the parent element of this element. If `position()` is called without arguments, it returns the current position. If `position({ parentRealtive: true })` is called without `x` and `y` coordinates and with the `parentRelative` flag set to `true`, the method returns the current position of the element relative to its parent. Setting `opt.deep` to `true` will position not only the element but also all its descendants keeping the original distances from a child to the element origin.

    el1.position(100, 100);
    el1.embed(el2);
    el2.position(10, 10, { parentRelative: true });
    el2.position() // --> 110@110
    el1.position(200,200, { deep: true });
    el2.position() // --> 210@210