Need to check more than the pathname.  Adding hostname check, since HTML5 pushstate only works on the same hostname.  Links to other domains will now work.
For relative links in i.e., the host shows up as blank, so the last fix broke ie.  A blank host really means the current host, so we can check to see if it's blank and assign the current host, then proceed.
If this.host is empty (which it is when using IE), set it to window.location.host.
Merge pull request #249 from marshallswain/master

Needed host check for pushstate.js