[fix #2530561] Slider updates. Skin assets now live in /build/slider-base, not /build/slider. Updates to Slider examples.

Duplicating slider-base skin files as slider skin files to support skin override in YUI config. Minified non-sam skin slider.css and slider-base.css (sam is done by the build process).

Updating sam skin

yui- to yui3- in classnamemanager and css files

Shifting rail background image

Moved css to assets - console, slider, widget, widget-stack