adding iOS like slideIn effect for banner

I had a usecase where the overlaying style was very uncomfortable, cause it hides important controls.
So i copied the native iOS behaviour to slide down the page to show the smartbanner.

To control this behaviour there is a additional option 'layer':boolean.

This has to main impacts:
- the javascript code set the position rather than only the css code, cause the slide cannot work with absolute positioning
- the initial smartbanner will be hidden (display:none / jQuery.hide())

In addition i replaced unescape and ecapse, cause those function are considered deprecated.

I hope somebody enjoys the feature - thx and keep on the n1ce work =]