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/schemas.spec.js

@@ -4,7 +4,7 @@ const Parse = require('parse/node').Parse;
 const request = require('request');
 const rp = require('request-promise');
 const dd = require('deep-diff');
-const Config = require('../src/Config');
+const Config = require('../lib/Config');
 
 let config;