Pull jQuery 1.4a2 into UI

Pull jQuery 1.4a2 into UI

I'd like to pull jQuery 1.4a2 (and any subsequent releases) into UI and update all files to use it. This will give us a little time to do some more thorough testing with 1.4 before it's released. UI 1.8 should be compatible with both 1.3.2 and 1.4.
Any objections?


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