A minor ("30" minute) hack to support widearea keepalive. If a remote
node connects with UDP, update the nodes table status with 'up' and the current time. This is the only thing that can happen when a remote node connects with UDP (since there is no ssl). The idea is that a daemon on the remote nodes will wake up periodically and send in a UDP packet that says its alive. Since the idea is to be low overhead, I'm using a UDP packet for now, which means I can run it fairly often on all the clients, without it being too much of a drain. By its nature, if the remote node can start up tmcc and get a udp packet out, its probably in good shape. Maybe we will find out this does not work, but if so I will have lost only "30 minutes". See related changes in db/node_status.in. Also, add the code that kicks out remote nodes that connect with tcp but no ssl (it was commented out while I originally updated the ron nodes with the new tmcc stuff).