long_format(): Now takes a third parameter, addL; iff true, a

trailing 'L' is appended to the representation,
                otherwise not.

                All existing call sites are modified to pass true for
                addL.

                Remove incorrect statement about external use of this
                function from elsewhere; it's static!

long_str():     Handler for the tp_str slot in the type object.
                Identical to long_repr(), but passes false as the addL
                parameter of long_format().