WSSQL-38 Column verification
- Corrected error messages
- Corrected order of column verification
- Delayed file access as columns processed
- Verify Group by columns as well

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
WSSQL-38 Changes from code review.

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
WSSQL-38 Further changes from code review.

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
Merge pull request #29 from rpastrana/WSSQL-38-SELECTALL-ORDERBY

WSSQL-38 Column verification