Created ssr demo and moved csr to a sub-folder + rebuild

demo/server_side_rendering/.nuxt/components/nuxt-link.js

@@ -0,0 +1,9 @@
+import Vue from 'vue'
+
+export default {
+  name: 'nuxt-link',
+  functional: true,
+  render (h, { data, children }) {
+    return h('router-link', data, children)
+  }
+}