Fix to bug #549, http://bugs.skysql.com/show_bug.cgi?id=549
Each monitor loops 10 times/second (sleep 100ms) and perform monitoring checks only when monitor's interval is spent. Monitors notice faster if the shutdown flag is set and thus overall shutdown is faster.
hint.c:added missing header
Changed interval from unsigned long to size_t which is guaranteed to be of same size also in windows (if possible).