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/EmailVerificationToken.spec.js

@@ -2,7 +2,7 @@
 
 const request = require('request');
 const requestp = require('request-promise');
-const Config = require('../src/Config');
+const Config = require('../lib/Config');
 
 describe("Email Verification Token Expiration: ", () => {