NTLM support for chained proxy

This is code proposal for LittleProxy to support preemptive NTLM authentication to a chained proxy.
In the class extending ChainedProxyAdapter, just set an NTLM handler to enable this feature.

setNtlmMessageHandler(new NtlmHandlerImpl(new JcifsNtlmProvider("myuser", "mypass")));

I have used http://jcifs.samba.org/ as default provider to generate NTLM messages, but any provider can be plugged in.