- refactored WqlSelect definitions
- refactored emitSelect method and started implementing group clauses of select statements
- added tests for select statements with group clauses
- removed semicolon
- added first wql2pig test for select statement with group clause
- added initial support of select with group to emitSelect
- fixing group relation name if there is a where statement before it
- added wql2pig test of select with both group and where clauses