Make rio.c comment 80-columns friendly.
Cluster: turn hardcoded node timeout multiplicators into defines.

Most Redis Cluster time limits are expressed in terms of the configured
node timeout. Turn them into defines.
Cluster: node timeout is now configurable.
Cluster: CONFIG GET cluster-node-timeout.
Cluster: move REDIS_CLUSTER_FAILOVER_DELAY near other timing defines.
Test: remove useless statements and comments from test default config.