add a option shiftRouterNameFromUrl for dispatcher

when this flag is true(default), act as yog2's default action.
when this flag is false, act as express's default action.

plugins/dispatcher/dispatcher.js

@@ -28,6 +28,11 @@ var VERB = {
 module.exports = function (options) {
     var defaultRouter = options.defaultRouter || 'home';
     var defaultAction = options.defaultAction || 'index';
+    var shiftRouterNameFromUrl = true;
+    if( options.hasOwnProperty(shiftRouterNameFromUrl) ){
+        shiftRouterNameFromUrl = !!options.shiftRouterNameFromUrl;
+    }
+
     var appPath = options.appPath || (path.dirname(require.main.filename) + '/app');
     debuglog('set options appPath [%s], defaultRouter [%s], defaultAction [%s]', appPath, defaultRouter, defaultAction);
     var routers = {};
@@ -55,7 +60,7 @@ module.exports = function (options) {
             return;
         }
         debuglog('actually get router [%s]', router.__name__);
-        if (router.__name__ === routerName && req.params.router) {
+        if (router.__name__ === routerName && req.params.router && shiftRouterNameFromUrl) {
             req.url = shiftUrl(req.url);
             debuglog('router is matched, remove router from url [%s]', req.url);
         }
@@ -86,7 +91,7 @@ module.exports = function (options) {
                 return;
             }
             debuglog('actually get action [%s]', action.__name__);
-            if (action.__name__ === actionName && req.params.action) {
+            if (action.__name__ === actionName && req.params.action && shiftRouterNameFromUrl) {
                 req.url = shiftUrl(req.url);
                 debuglog('action is matched, remove action from url [%s]', req.url);
             }