enables AngularJS to use any jQuery, implementing issue #608

Enables AngularJS to use any jQuery library by using the `window.angularjsUseJquery` variable, that can have the following values:
  * undefined / null / false - the default behavior (try to use window.jQuery, if not, use internal)
  * "internal" - use the internal jQuery lite, no matter which other jQuery is present in the page
  * reference to any variable containing a jQuery instance