Never call both new and show resource actions

This the cleanest fix I was able to think of. I couldn't find a regexp based solution.

The problem existed already before my multiple route matching PR. All the examples defined show action after new action. V8 ```for in``` loop iterates attributes in the order they are added to the object. The following I think would have failed:

```
app.resource('users', {
  // GET /users/:id
  show: function *(next) {
  },
  // GET /users/new
  new: function *(next) {
  }
}
```