enable multi-phase aggregate by default
DRILL-764: Add support for 'convert_to()' and 'convert_from()' functions from SQL
DRILL-671: Select against hbase table with filter against row_key fails
DRILL-783: Convert function support in HBase filter push down.

+ Enable HBase test suit (failures fixed by DRILL-761).
DRILL-781: Use MapVector as the top level vector for HBase Column Families