handle problems with default ports and redirects

Hi,

This is a problem encountered by every HTTP library and most of them address this. I wasn't sure how best to write a test for it for you, so direction would be helpful.

The issue is that Apache + Wordpress, when issuing redirects, treat `Host: hostname.com:80` as different from `Host: hostname.com`. This means that in almost all cases, it is safer to drop the `:80` from the `Host: ` header in HTTP requests and the `:443` from HTTPS requests.