Improve restart when provided bad args.

Bad args exit immediately.  This commit ensures that repair is not necessary
after restart.
Log when quorum causes reject
Check pending signals on each iteration of event loop
Change the ping pattern to work better with TCP
Improve stability reporting
Scale the size of the window used for healing
Only grow the chain one node at a time
Change suspicion calculation.

If there are too few pings, or they don't cover a sufficient interval, return
HUGE_VAL.  The previous version would return 1.0 when servers were suspected.
Tighten the transfer window
Include duplicate samples in the failure detector.
Improved cluster maintenance algorithm.

The new algorithm strives to minimize changes to the configs, and thus reduce
the number of times the system configures itself.
Improve post-reconfiguration time