remove `next` in callback for now

revisit mounting later

lib/application.js

@@ -97,11 +97,10 @@ app.callback = function(){
   var fn = co(gen);
   var self = this;
 
-  return function(req, res, next){
+  return function(req, res){
     var ctx = self.createContext(req, res);
-    next = next || ctx.onerror;
-    ctx.onSocketError(next);
-    fn.call(ctx, next);
+    ctx.onSocketError(ctx.onerror);
+    fn.call(ctx, ctx.onerror);
   }
 };