dal.py: Table class: validate_and_update_or_insert method created, and minor changes in validate_and_update
dal.py: Table class: validate_and_update_or_insert method created, and minor changes in validate_and_update

niphlod/pydal,kmcheung12/pydal,web2py/pydal,stephenrauch/pydal,willimoa/pydal,michele-comitini/pydal,manuelep/pydal