Wrong protocol identification for relative URL with colons

I think to have found a minor issue, in URI parsing.

You can replicate this issue using the Wikipedia links. For example, parsing a local URL on Wikipedia:

``` html
<a href="/wiki/Help:IPA">....</a>
```

the URI.parse() method returns for protocol

```
/wiki/Help
```

and for path

```
IPA
```

and this is clearly wrong.
