koajs/koa — pull request #56 by jonathanong (2013-10-04 06:55:57+00:00)
Title: bind .onerror to context

so we don't have to do

```js
stream.on('error', this.onerror.bind(this))
```

every time and just do

```js
stream.on('error', this.onerror)
```