fix(docs): run from file:// url again

src/templates/index.tmpl

@@ -18,12 +18,18 @@
     // before the base attribute is added, causing 404 and terribly slow loading of the docs app.
     (function() {
       var indexFile = (location.pathname.match(/\/(index[^\.]*\.html)/) || ['', ''])[1],
-          rUrl = /(#!\/|<%= sections %>|index[^\.]*\.html).*$/,
-          origin = location.origin || (window.location.protocol + "//" + window.location.hostname + (window.location.port ? ':' + window.location.port: '')),
-          baseUrl = origin + location.href.substr(origin.length).replace(rUrl, indexFile),
+          origin, baseUrl, rUrl = /(#!\/|<%= sections %>|index[^\.]*\.html).*$/,
           headEl = document.getElementsByTagName('head')[0],
           sync = true;
 
+      if (location.href.slice(0, 7) == 'file://') {
+        baseUrl = location.href.replace(rUrl, indexFile);
+      } else {
+        origin = location.origin || (window.location.protocol + "//" + window.location.hostname +
+                                    (window.location.port ? ':' + window.location.port: ''));
+        baseUrl = origin + location.href.substr(origin.length).replace(rUrl, indexFile);
+      }
+
       addTag('base', {href: baseUrl});
       addTag('link', {rel: 'stylesheet', href: 'css/bootstrap.min.css', type: 'text/css'});
       addTag('link', {rel: 'stylesheet', href: 'css/font-awesome.css', type: 'text/css'});