Merge branch 'jquery-ui' into 'dev'.

    * Create wire/jquery/ui containing
        - a "widget" factory that accepts a node, type, and options
        - proxy overrides for get, set, and invoke methods
        - automatic generation of getters and setters
    * Create unit tests and a demo page for wijmo widgets
    * Create documentation
    * Modify wire/jquery/on and wire/lib/plugin-base/on to pass
      extra jquery-ui params to event handlers