Rewrite convert_from/ convert_to functions to actual function implementations
DRILL-1061: Disable MergeProjectRule if project expression has complex output type
DRILL-1164: Use FQCN while casting Timestamp to Date
DRILL-1126: Support generic objects as workspace variables in UDAF
DRILL-1177: Check if setsafe() succeeded while performing HashAggregation
DRILL-1086: invalidate PStore to drop a view in case it is not in the underlying fs
DRILL-1090: Shutdown Drillbit if start-up fails
DRILL-1096: Stop ScanBatch if read fails and pass failure context to the client, break the producer loop when iter outcome is stop
DRILL-1119: updated error message thrown when schema is immutable
DRILL-1144 Fix cases where leading zeros are ignored in decimals
DRILL-1181: Generate user friendly error messages