Build: Update license

Closes gh-1257
Slider: Reset positioning when orientation changes

Fixes #10105
Closes gh-1268
Progressbar: replace image reference in base CSS with data URI

The CSS for the Progressbar widget contained a reference to
"images/animated-overlay.gif", which is not included in custom jQuery UI
builds with "no theme" selected. This replaces the reference with a data URI.

Fixes #10134
Closes gh-1276
Theme: Add support comments for filter properties
Dialog demo: Remove a duplicate (and incorrect) script include