First implementation of Kerberos token reuse.

- Gave stdin and stdout thread simper names.
- Factored HTTP handling code out of WinRmClient into WinRmHttpClient (kinda like the old HttpConnector class but now with state).
- Each thread (main, stdin, stdout) gets its own WinRmClient/WinRmHttpClient combo which means each thread has to authenticate once -> too many Kerberos call and too many HTTP calls.
- Shell and command ID are passed to the stdin and stdout WinRmClients using a package scope field. :-(
- No encryption yet.
- No preemptive authentication yet.