normalizes a file to a URL pathname
A simple function to normalize a file path into a URL path that can be used when testing req.url from an HTTP server.
``js
var toUrl = require('normalize-file-to-url-path')
toUrl('./foo.js')
//=> 'foo.js'
toUrl('foo bar.js')
//=> 'foo%20bar.js'
toUrl('/')
//=> null
``
Experimental -- mostly used internally across some of my tools.
MIT, see LICENSE.md for details.