If a child process dies in a way that it can't recover from, the main
process now exits, to prevent loops of 'Error: channel closed'
thousands of times a second, filling up the error log and making it
hard to track down the real error.
Specifically, Users.users, Users.connections, and Users.pastUsers
are now ES6 Maps. In theory, this should be a minor performance
upgrade, but we still need to profile to make sure.
