URL namespaces, bug fixes, and test updates

This version includes a big update to the QUnit tests and the testing setup. In addition to updating the QUnit version, we're now using the new API and the tests are a bit more mainatainable and easier to find. Additionally, there were some bug fixes for cross domain requests and proxy data. And we have a new feature: global URL namespaces!

Thanks to @danpaz you can now do:

$.mockjaxSettings.namespace = "/api/v1";
$.mockjax({
  url: "/rest"
});
$.mockjax({
  url: "/foobar"
});

$.ajax({
  url: '/api/v1/rest',
  // ...
});
$.ajax({
  url: '/api/v1/foobar',
  // ...
});

Many thanks to the folks that helped with the work in this release: @danpaz, @stas-vilchik, @udnisap, @gyoshev, @LeopoldoFu, @r4j4h, and @ScottONeal