proxy-ignore-hosts, feature request.

[akacase]

http-kit/src/java/org/httpkit/client/HttpClient.java

Line 283 in 6bbb88c

if (cfg.proxy_url != null) {

I'd like to propose a feature for parity with clj-http, the ability to "ignore" certain hosts via the proxy-ignore-hosts variable, if set, this'll trigger a simple regex to ensure that we don't pass the URL through the proxy. Any issues with this? It seems fairly straight forward to implement, unless I'm missing something. I'm willing to implement, just checking if there's a problem before hand.