Update jQuery to 1.10.1 including jQuery Migrate.

NOTE: The jQuery Migrate plugin is only included temporarily for
      debugging purposes. If and when everything (including plugins
      and themes) is tested with jQuery 1.10.1, Migrate can and
      will be removed.

      The reason for this is that jQuery 1.9 deprecates some stuff,
      see http://jquery.com/upgrade-guide/1.9/. If core, plugins or
      themes use a deprecated feature, jQuery Migrate will note it
      in the browser's JS console.