Router updates + unit tests + React

- added -f flag to run unit test command in order to fail fast
- pass only id to "$endpoint->get($id)" in React forms instead of array
- updated routers according to the ->get($id) change
- refactored a bit the way form creation works
- added unit tests for Segments router

assets/js/src/form/form.jsx

@@ -48,7 +48,7 @@ define(
         MailPoet.Ajax.post({
           endpoint: this.props.endpoint,
           action: 'get',
-          data: { id: id }
+          data: id
         }).done(function(response) {
           if(response === false) {
             this.setState({