refactor(core): add router

src/core/global-api.js

@@ -0,0 +1,13 @@
+import * as util from './util'
+import * as dom from './util/dom'
+import * as render from './render/compiler'
+import * as route from './route/util'
+import { get } from './fetch/ajax'
+import marked from 'marked'
+import prism from 'prismjs'
+
+export default function () {
+  window.Docsify = { util, dom, render, route, get }
+  window.marked = marked
+  window.Prism = prism
+}