only throw NoAggregateWithGroupByExceptions when there are aggregates in the subquery
comments, style
add another test
added output check to test
Merge pull request #2 from hchandl/aggregateMapperError2

added output check to test
added row_count: 0
Merge remote-tracking branch 'fdb/master' into aggregateMapperError
fix test
merge hchandl: Stop AggregateMapper from throwing an error for valid column reference

Merge pull request #1559 from hchandl/sql-layer/aggregateMapperError
https://github.com/FoundationDB/sql-layer/pull/1559