Parse location.href with an anchor for IE

This is a follow up to https://github.com/madrobby/zepto/pull/1046. It turns out that IE always adds the port to `window.location.host`, but not to `a.host`. This doesn't show up in tests because they are run on port 3000, so the port is always present in `a.host` too.
IE is great!

![](https://cloud.githubusercontent.com/assets/1144197/5400694/98cf1de0-8132-11e4-8221-719c9307c499.png)