DRILL-1873: Fix boolean type writing in parquet record writer.
DRILL-1825: In ProjectRecordBatch, avoid  requesting memory (will result in memory leak) when no output column is needed
DRILL-1828: In ProjectRecordBatch, add a case for expression classification
DRILL-1561: Add test case for doing 2 phase aggregation after order-by (already fixed by DRILL-1846).
Add IO Stats

Refactoring: Remove FileSystem shim loader