IPv6 Requests fail with Exception

When making a request to a http-kit server via IPv6 the request fails with an exception

```
Mon Apr 15 11:51:07 CEST 2013 [server-loop] ERROR - http server loop error, should not happen
java.lang.NumberFormatException: For input string: "xxxx:xxxx]:8000"
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
	at java.lang.Integer.parseInt(Integer.java:492)
	at java.lang.Integer.valueOf(Integer.java:582)
	at org.httpkit.server.HttpRequest.setHeaders(HttpRequest.java:81)
	at org.httpkit.server.RequestDecoder.readHeaders(RequestDecoder.java:166)
	at org.httpkit.server.RequestDecoder.decode(RequestDecoder.java:89)
	at org.httpkit.server.HttpServer.decodeHttp(HttpServer.java:84)
	at org.httpkit.server.HttpServer.doRead(HttpServer.java:153)
	at org.httpkit.server.HttpServer.run(HttpServer.java:229)
	at java.lang.Thread.run(Thread.java:722) 
```

I have not made any extensive IPv6 tests but at least the request gets served properly when port parsing is done via .lastIndexOf.