#410 implementation of testing SJS modules with SJS

[dmcassel]

Allows tests like the one below. I'll add or update a wiki.

var test = require('/test/test-helper.xqy');
var simple = require('/lib/simple.sjs');

(function addOnePlusOne() {
  var actual = simple.addOne(1);
  xdmp.log('Ran addOnePlusOne');
  return [
    test.assertEqual(2, actual),
    test.assertNotEqual(5, actual)
  ];
})();

(function addOnePlusTwo() {
  var actual = simple.addOne(2);
  test.assertEqual(3, actual);
})();

[dmcassel]

https://github.com/marklogic/roxy/wiki/Unit-Testing#testing-with-server-side-javascript

[dmcassel]

@grtjn I made that update you suggested. You good with this PR?

[grtjn]

Looks good to me.