foo.bar.com should load foo.bar.com.js, bar.com.js and com.js

quote from https://github.com/defunkt/dotjs 

```
On subdomains such as http://gist.github.com dotjs will try to load
~/.js/gist.github.com.js as well as ~/.js/github.com.js and ~/.js/com.js.
```

I would love to see this behaviour here as well.
this is particular useful for pages that redirect around between sub domains.
