Add extra logging. Add detailed message to one very annoying assertion :)
Remove the Process from waiting_to_start in on_process_down. Process is gone, so we don't bother killing it in verify_process_alive.
Simplify the assertion message.
Make sure all fds are removed from the hub when process is cleaned up.
Change the log message to be a warning instead of critical.
Cleanup the active_writes set too.
Merge pull request #1834 from ionelmc/fix-1785

Better cleanup of dead processes.