Button: fixed inconsistent button styling in most browsers. Fixes #7996 - Button: Inconsistent styling based on markup
Theme: removed or changed occurrences of zoom. Fixes #7975 - Remove invalid CSS for legacy browsers

Because of overlapping issues, this also reverts most of e77edc60 and fixes it in a different way.
Progressbar: Create and destroy indeterminate overlay as needed and code cleanup.
Progressbar: Add custom label demo.
Dialog: Ensure all animations finish and clean up themselve when destroying dialog. Fixes #5860 - Dialog: Destroying a dialog during animated close leaves .ui-effects-wrapper in DOM.
Grunt: Set testswarm/browserSets from JSON file.

File on jq03.jquery.com is already updated.
Resizable: Respect containment for alsoResize option. Fixes #4603 - Resizable: alsoResize option doesn't work with containment. Fixes #5559 - Dialog: Content grows bigger than widget on resize at document edge.
Dialog: Restrict title to a single line. Fixes #7773 - Dialog: If titlebar changes height during resize, button pane positioning changes.
Dialog: Adjust southeast resize handle to not be visible and more closely match other resize handles. Fixes #4575 - Dialog: Scrollbar is difficult to use with overflow content and resize handle.
Widget tests: Fixed order of actual and expected.
Widget: Don't modify the prototype passed to $.widget(). Fixes #8876 - Calling _super calls wrong inherited widget.
Dialog: Cleanup style properties on _destroy. Reenables style check in domEqual, while removing commented and unnecessary old code. Fixes #8119 - Dialog: Destroying a dialog leaves style, scrollleft, and scrolltop leftovers.
Menu: Remove display property on hidden submenus instead of setting display:block. Surfaced by domEqual now checking for style property (see d687a1b).
Tabs: Remove display property on hidden panels instead of setting display:block. Surfaced by domEqual now checking for style property (see d687a1b).
Dialog: Remove the instance-storing for the overlay, just create one whenever it is needed. Heavily simplifies the code, while the memorly leak should be hardly an issue anymore, since fixed positioning restricts the overlay size to the window dimensions. Fixes #6058 - Dialog overlays are not properly reused when multiple instances of a Dialog exist.
Dialog: Refactor _createOverlay and _destroyOverlay to use widget methods and properties.
Progressbar: Custom label demo cleanup
Revert "Tabs: Remove display property on hidden panels instead of setting display:block. Surfaced by domEqual now checking for style property (see d687a1b)."

This reverts commit b9068c1523f39da8a04c799eebc9adc8b83c7279.
Revert "Menu: Remove display property on hidden submenus instead of setting display:block. Surfaced by domEqual now checking for style property (see d687a1b)."

This reverts commit 53b940fa27fc50b4663eef77249a9afce4129240.
Revert "Dialog: Cleanup style properties on _destroy. Reenables style check in domEqual, while removing commented and unnecessary old code. Fixes #8119 - Dialog: Destroying a dialog leaves style, scrollleft, and scrolltop leftovers."

This reverts commit d687a1b10d1e176a6a8dd4420f1ea3a890640da0.