Add support for SQL DISTINCT on multiple columns and expression
Add sql coverage tests for DISTINCT on multiple columns and expression; Fix the existing unit tests
Add the fix for DISTINCT on table aggregate
Merge branch 'master' of github.com:VoltDB/voltdb into ENG-6436-distinct-reroute
Merge pull request #1794 from VoltDB/ENG-6436-distinct-reroute

Eng 6436 distinct reroute