[MONDRIAN-1471] The fields in QueryTiming were accessed by multiple threads w/o synchronization, leaving the possibility of stale data.  Added synchronization on public methods.
[MONDRIAN-1471] Added a BlockingHashMap implementation, which replaces the ResponseQueue in SegmentCacheManager and MonitorImpl.  The ResponseQueue blocked all threads attempting to fetch their response,
whereas this implementation blocks on the get of individual items within the Map.
[MONDRIAN-1471]  Moved shutdown of the ExecutorService into a finally block.
Merge pull request #89 from mkambol/mondrian-1471

[MONDRIAN-1471] The fields in QueryTiming were accessed by multiple thre...