Run an animation of a given element to a new position, optionally setting duration in seconds (0.25 by default) and easing linearity factor (3rd argument of the cubic bezier curve, 0.5 by default)
You can also use the following shortcut when you just need to make one additional method call.
You use L.Class.extend to define new classes, but you can use the same method on any class to inherit from it.
Creates a PosAnimation object.