Added extra debugging to query_classifier to assist in issue resolution regarding to optimized MaxScale builds and pthread_mutex_lock in sql/sql_class.h
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).
