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/Logger.spec.js

@@ -1,4 +1,4 @@
-const logging = require('../src/Adapters/Logger/WinstonLogger');
+const logging = require('../lib/Adapters/Logger/WinstonLogger');
 const winston = require('winston');
 
 class TestTransport extends winston.Transport {