polyfit: add a third output argument, mu [PATCH]

[David Bateman]

Ben Abbott wrote:
> Hey guys,
>
> A changeset was applied back in Feb that includes the third output 
> argument, mu.
>
>     http://www.nabble.com/Re%3A--changeset--Polyfit-with-scaling-p15834853.html 
>
>
> I checked my copy of jwe's default archive, and it is present there. 
> Is it not in yours?

Ok, so what else is in wpolyfit.. It is always better to not have two 
versions of the same function, as thats just a source of confusion, so 
it would be better to cut any beneficial code from wpolyfit and port it 
to Octave.

D.