output = MakeMonotonic(input)
Make input monotonically increasing.
See also MakeGammaMonotonic, which is probably what you want if you are fitting
gamma functions. This routine left alone when MakeGammaMonotonic was created,
in case it is called from programs completely unrelated to gamma fitting.
3/1/99 dhb Handle multiple columns.
8/03/07 dhb Old routine just enforced non-decreasing. Fixed to make strictly increasing.
3/07/10 dhb Added comment about MakeGammaMonotonic.