drill

8ab361b1 - DRILL-2275: Added support to get information about current cluster memory and threads

DRILL-2275: Added support to get information about current cluster memory and threads + SystemRecordReader reads a SystemRecord e.g. MemoryRecord + Added generic data type for static tables + GroupScan can enforce width to be maximum width on ExcessiveExchangeRemover + GroupScan has minimum width for SimpleParallelizer