Merge branch 'next' into sam_3815_alt
Merge branch 'next' into sam_3815_alt
Made evicters_per_thread be per_thread_data, no substantive change yet.
Merge branch 'next' into sam_3185_alt
Made evicter->balancer wakeup notifications, but balancer never sleeps yet.
Renamed frequency_ms parameter to the more reciprocally accurate name, period_ms.
Made cache_balancer_t::rebalance_timer be in a scoped pointer.
Made existing old cache balancer shut down and restart.
Gave the evicter its own drainer to make shutdown happen properly.
Merge branch 'next' into sam_3185_alt
Merge branch 'sam_3185_alt' into next