allows add multiple submit buttons in "selectable" mode in SQLFORM.grid (with different decorate css classes)
allows add multiple submit buttons in "selectable" mode in SQLFORM.grid (with different decorate css classes)

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