Interoperating: Redcreek Ravlin

Known issue #1: The Ravlin expects a quick mode renegotiation right after every Main Mode negotiation.
Known issue #2: The Ravlin tries to negotiate a zero connection lifetime, which it takes to mean "infinite". Jim Hague's patch addresses both issues.
Interop works with Ravlin Firmware > 3.33. Includes tips (PSK).