faster factorial



>>>>> "Raymond" == Raymond Toy <raymond.toy at ericsson.com> writes:

    Raymond> I think I can do that.  But I can't guarantee it won't break anything
    Raymond> else; I can only guarantee it won't break the test suite.

Done, and the test suite passes fine.  I'll check it in shortly.
And, interestingly, my first attempt at this failed to handle the case
0! = 1 and returned 0 instead (because (k 0 1) returns 0), which the
test suite caught, indirectly.  Nice.

Ray