Refactor CLI and add tests

src/server/index.js

@@ -0,0 +1,12 @@
+var express = require('express')
+
+module.exports = {
+  create: function () {
+    var server = express()
+    server.set('json spaces', 2)
+    return server
+  },
+  defaults: require('./defaults'),
+  router: require('./router'),
+  rewriter: require('./rewriter')
+}