Slider: Create a copy of the options.values array for the return value of _value().  Fixes #4751 - Dragging slider modifies values, even if callback returns false.
Slider: Create a copy of the options.values array for the return value of _value().  Fixes #4751 - Dragging slider modifies values, even if callback returns false.

Thanks bkrausz.

GrayYoung/jQuery.UI.Extension,GrayYoung/jQuery.UI.Extension