fix(mocha): fix vue-router creation using mocha (#128)

* fix(#119): allow routes vue-router creation through routes param from both jest and mocha

* add test to check vue-router require for mocha users

* fix Vue Router require to be compatible with CommonJS

* delete deprecated test

src/vue-testing-library.js

@@ -36,7 +36,8 @@ function render(
   }
 
   if (routes) {
-    const VueRouter = require('vue-router') || require('vue-router').default
+    const requiredRouter = require('vue-router')
+    const VueRouter = requiredRouter.default || requiredRouter
     localVue.use(VueRouter)
     router = new VueRouter({
       routes,