allow usage from machines other than localhost

Hi,

great tool for cross platform livereload.
I wanted to run the server on my development box (virtualized ubuntu) and browse the website on chrome for windows, ie: make the server listen to hosts other than `localhost`.

With this patch it's possibile to issue:

```
livereloadx --hostname=*
```
from the command line and the server will listen from connection coming from other machines.

**Note:**

Chrome extension still injects a script pointing to `http://localhost:...` so you'll need to add the snippet manually to your pages.

On that side a good technique to prevent blocking page load if the livereload server is down or slow, would be to replace the `document.write` snippet with its async version:

```html
<script>
		(function () {
	        var w = document.createElement('script');
	        w.type = 'text/javascript';
	        w.async = true;
	        w.src = 'http://' + (location.host || 'localhost').split(':')[0] + ':35729/livereload.js?snipver=2';
	        var s = document.getElementsByTagName('script')[0];
	        s.parentNode.insertBefore(w, s);
		}());
</script>
```