router: change order of arguments

fixup! freeze state & rename app ns to location

examples/mailbox/elements/mailbox.js

@@ -2,7 +2,8 @@ const dateformat = require('dateformat')
 const html = require('../../../html')
 
 module.exports = function () {
-  return function (params, state, send) {
+  return function (state, prev, send) {
+    const params = state.params
     const mailbox = params.mailbox
     const message = params.message
     const messages = state[mailbox].messages