fishnet v1.17.2

• Reduce maximum move time from 20s to 6s. Clients that frequently hit this
  limit should be stopped in favor of clients with better hardware.
• Support future proof constants --user-backlog short and
  --system-backlog long (to be used instead of hardcoded durations).
• Fix some ignored command line flags during python -m fishnet configure
  and on intial run.