ui.widget: Improves Performance of cleanData-Method. Fix for http://bugs.jqueryui.com/ticket/9546

[felvhage]

The cleanData-Method triggered "remove" on all elements in the tree.
After the fix the remove-handler will only be triggered if there is at least
one event bound to the element. Doing so increases performance significantly.
performance-comparison http://jsfiddle.net/felvhage/r7buw/

Fixes #9546

[scottgonzalez]

Thanks. Please complete the following tasks (covered by our contributing guidelines):

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You can probably save even more time by specifically checking for a remove property.

[scottgonzalez]

Replaced by #1291.