Misultin websockets doesn't work with Firefox 6

Firefox 6.0.2 is using ws version 7:

```
Sec-WebSocket-Version: 7
```

Misultin doesn't seem to have a support for that. Example:

```
GET /websocket HTTP/1.1
Host: localhost
Connection: a, Upgrade
Upgrade: websocket
Sec-WebSocket-Key: el8cYBMT/wMIHMCs8v2tjQ==
Sec-WebSocket-Origin: http://localhost/
Sec-WebSocket-Version: 7
```

Doesn't work (goes to http handler), while version: 8 works fine.
