Change the way Express gets hostname

[simison]

Getting host via req.get('host') instead of req.hostname.

get() methods adds also port if it's something else than 80.

Otherwise links that should be "localhost:3000" end up being just "localhost".

[simison]

On second thought, nope.

This would've been great for stuff like:
<link href="http://localhost:3000/modules/core/img/favicon.png" rel="shortcut icon" type="image/png" />

But I overlooked this:
<script type="text/javascript" src="http://localhost:3000:35729/livereload.js"></script>

I think on my own version I'll just pass separate hostPort and host parameters, but dunno what's the best for the boilerplate.

Sorry noise. :-)