1. make sure that a C record is sent for node call every update period.
2. make announces work again (probably).
3. Fix long standing possibility of a crash with a new user.
+4. Add continuous chatting (like talk with no message eg 'chat #9000' just on
+its own with no message).
24Jun07=======================================================================
1. Fix the routing algorithms to allow route selection in the face of
incomplete trees of nodes (trees as produced by sh/newc).