DRILL-692: Add Hive UDFs to Drill SQL operator table.
DRILL-683: Qualify HBase scan with specified columns even if row_key is required.

 + Added some log messages
DRILL-686: Verify the operands while extracting projects that can be pushed into a scan
DRILL-696: Use standard HBase configuration name/value in HBaseStoragePluginConfig
DRILL-695: Push down column value predicates into HBase scan
DRILL-529: 'atom' rule in Antlr grammar uses wrong token for calculating ExpressionPosition
DRILL-567: Maven RAT plugin - Ignore all files inside a hidden directory ".*/**"
DRILL-691: Function alias to be able to cast to TIMESTAMPTZ data type
DRILL-690: Generate 2 phase plans for Hash Aggr and Streaming Aggr only if the aggr functions are SUM, MIN, MAX.

Added session options for enabling/disabling aggrs, joins and multiphase aggrs.  Modified DrillRuleSet to populate the rules based on options rather than from static list.  Added matches() implementation for join and aggr rules.
Disable multiphase aggregation.
Enable class unloading in unit test.
DRILL-607, DRILL-593: Fix casting from Int, BigInt to Decimal28, Decimal38
DRILL-608: Fix casting to decimal data types with difference scales.