New client/server components:

- broke out all common functions to "common" file
- put all client commands into "monkeysphere" script
- put all server commands into "monkeysphere-server" script
- moved all code into src directory to clean things up a bit
- this effectively makes obsolete rhesus and howler
- added proposed monkeysphere-ssh-proxycommand script that can be
  called to update known_hosts from ssh ProxyCommand
- updated monkeysphere.conf to work as global client config
- added monkeysphere-server.conf for server config