made it work with touch events and bit faster on low-end devices

Now works with touch events
initilization should be faster becauser of only one dom insertion per
instance
its now harder to accidently rewrite css rules
its now easier to customize default look of slider (added demo)
made demo page look better and more supported in mobile browser
updated jquery version
added active class to slider handles
commented out "slider-unselectable" because i couldn't reproduce the
problem

did not update minified js file.