Removes need to use babel-register (#4865)

* Removes need to use babel-register

- Adds watch to watch changes when running the test to regenerate
- Tests are now pure node 8

* Adds timing to helper.js

* Update contribution guide

* Adds inline sourcemaps generation to restore coverage

* nits

spec/AccountLockoutPolicy.spec.js

@@ -1,6 +1,6 @@
 "use strict";
 
-const Config = require("../src/Config");
+const Config = require("../lib/Config");
 
 const loginWithWrongCredentialsShouldFail = function(username, password) {
   return new Promise((resolve, reject) => {