support for persistent-odbc
cleanup code for pull request #164
oracle and mssql changes for handling rational numbers
add limit offset handler
support for more generic per dbms limit and offset using connLimitOffset callback
support for mssql blob insert:need to pass fieldtype and fieldvalue to conninsertsql
add cDefaultConstraintName to Column for mssql as it uses a constraint for default values
Merge pull request #164 from gbwey/master

support for persistent-odbc