Catch InvalidArgumentException

Hello guys!
I think it could be related with #15
Steps to reproduce this crash:
- launch a server (just server.php from example)
- send wrong header (without \r\n):

`printf "GET / HTTP/1.0" | nc localhost 8000`

At this moment wrench tries to check header:
Method [validateRequestHandshake](https://github.com/varspool/Wrench/blob/master/lib/Wrench/Connection.php#L227) uses [getRequestHeaders](https://github.com/varspool/Wrench/blob/master/lib/Wrench/Protocol/Protocol.php#L720) and if there is no `"\r\n"` in `$response` it throws `InvalidArgumentException:`
```php
       if ($eol === false) {
            throw new InvalidArgumentException('Invalid request line');
        }
```
The main problem is that nobody catches this exception! =(

There are a lot of methods to solve this problem:
- change exception class
- add catching somewhere else
- catch main exception class from user application (server.php for example)

If you have other opinion about this problem, just say =)