upgrade to jQuery 1.11.1 and jQuery-UI 1.11.0. #778

This now pulls all data from official jQuery sources. Either their CDN
or their github account. Google tends to serve outdated or even broken
files :-(

Unfortunately there's no simple way to get the latest stable jQuery-UI
so for now the version has to be adjusted manually in the script.
Merge pull request #788 from splitbrain/jquery

  update jquery and jquery-ui