DRILL-793: Fix output type's scale and precision for math functions.
Add alias names date_diff, date_sub alias to date subtraction functions
DRILL-976: Fix extract second to return only second portion of interval; exclude hours, minutes
DRILL-995: Removed inner form (which is not allowed). Fixed NPE and URLs.
Improve error messaging for OperatorStats assertion messages.
DRILL-1001: Expanded ProfileWrapper content and formatting.
DRILL-699: Allow case insensitive function names in queries.
DRILL-842: Aggregate function for correlation coefficient calculation
Enhancements to capture HashAggregate and HashJoin runtime metrics.