Add checking in setMaxRows, setQueryTimeout, and setFetchSize

Problem:
 - If you try to setMaxRows(), setQueryTimeout() or setFetchSize()
to negative values, it should throw an exception, but doesn't. JDBC CTS
test failures.

Fix:
 - Added new error messages to errors.properties file.
 - PSQLExceptions thrown when user attempts to set negative values.

Cheers,

Kim