Provides a high-level interface for using "rendezvouses," a special type of
client-to-client communication used by such things as file transfer and direct
IM.
Functionality includes high-level handling of "rendezvous commands" inside
{@linkplain net.kano.joscar.snaccmd.icbm.AbstractRvIcbm ICBM's} as well as a
concept of "rendezvous sessions."