plt/racket — pull request #166 by pmechai (2012-11-06 22:36:22+00:00)
Title: path->url: ensure directory paths have a trailing slash

If a path to a directory is converted to an URL it loses its trailing path separator.
This can lead to a bug if the URL is used as a base URL to build other URLs (e.g. combine-url/relative).

For instance:
```racket
> (define u (path->url "/tmp/"))
> (require net/url)
> (define u (path->url "/tmp/"))
> (url->string u)
"file:///tmp"
> (url->string (combine-url/relative u "foo.txt"))
"file:///foo.txt"
```