Remove url fragments from host name

When working with tld.js I thought it might be useful if tld.js would also work with host names containing url fragments:

```javascript
tld.getDomain("http://fr.google.com/some/path")
// should return 'google.com' imho
tld.tldExists('https://user:password@example.co.uk:8080/some/path?and&query#hash');
// should return `true`
tld.getSubdomain('https://moar.foo.google.co.uk');
// should return `moar.foo`
```

The pull-request contains tests for this feature and updates the README accordingly.