$base_uri argument, and cleanup

I added a the `$base_uri` argument for this example:

- **url**: `http://external.example.org/handler-base/path/to/resource`
- **proxy_url**: `http://internal.example.org/proxy-base`
- **REQUEST_URI**: `/handler-base/path/to/resource`

`/handler-base` is where `.htaccess` and `index.php` live. Without stripping the **base_uri**, the **translated_url** looks like:

    http://internal.example.org/proxy-base/handler-base/path/to/resource

The whitespace cleanup just came with saving from my IDE.

---

I'm not sure how you feel about pull requests or if you are interested in doing a little more with this project, please let me know, and thanks!