[MONDRIAN-1471] Check the global cache-enabled flag only once per query. Mondrian's properties are based on a Hashtable, which is not performance-safe for use in tight methods like FastBatchingCellReader.get(RolapEvaluator).
Merge pull request #56 from sarahgerweck/FasterCacheCheck

Check the global cache-enabled flag only once per query. Short-term fix to MONDRIAN-1471, "Extreme contention between queries".