Slider: Remove unused variable

sliderLabel variable is not used.
Popup: Move _create and _enhance to the top of the widget.
Popup: Get rid of the call to _setOptions from _create.
Demos: Popup arrow: Let the mouse pass through the box showing where the arrow will point to.
Popup arrow: The "arrow" option now accepts the sides on which the arrow may show up, the extension no longer assumes that _setOptions() will be called from _create, and class names have the ui-popup- prefix.
Popup Arrow: CSS: The border now needs to be specified for it to appear.
Popup arrow: CSS: Moving corner-related stuff to theme.
Popup arrow: CSS: Getting rid of the quirky IE7 clip statement.
Popup arrow: visibility: hidden is better than pointer-events: none.
Demos: Popup widget: Add arrow demo.
tables/fix 6255: get colspan vs. data-colspan
Merge pull request #6256 from frequent/fix6255

tables/fix 6255: getAttribute colspan vs. data-colspan
Demos: View source: No need to parse HTML when all you want is a text node.
Fixed toolbar: Adjusted the page padding we set in the CSS to prevent jumping content.

The height of toolbars with a heading is now 45px.
Core: Min height for empty toolbars. Fixes #6258.
Moved grunt task loading after the initConfig call
Demos: Filterable: Re-worked to reflect the current state of the widget. Fixes #6227, #6229, #6230, #6231.
Filterable backcompat: Prevent default on generated form submit and blur input. Fixes #6226.

See 336db34e031b0815c807554796519cd34d28c153 and #3303.
Navigation: Do not submit forms via AJAX if the "submit" event default is already prevented.
Popup: Remove initSelector from options.