Reverting r88607. This downgrades jQuery from 1.5.2 back to 1.4.4.

Reverting r88607. This downgrades jQuery from 1.5.2 back to 1.4.4.
* The main reason being the problems with $.ajax that arose in UploadWizard (as remarked on wikitech-l).
* My plan is to take the following week (or two) to talk a bit about JavaScript unit testing and how we plan to do distributed continuous integration testing for it. After that we could upgrade right to 1.6.1
* See also bug 28904 and "[Wikitech-l] Any issues with pending jQuery 1.6.1 update on trunk?"