Support environments other than node.js that have a global URL class

[jesseditson]

There are a few environments that have become popular in the last few years that provide a native URL class - this includes v8 Isolates (cloudflare workers), and most/all modern browsers.

This library fails in these environments due to require('url'), which is unnecessary in those environments.

It should be fairly straightforward to detect the native URL object and fall back to a require only if it is not present, which would easily add support to a few new platforms.