found a small bug in residue corection

[Doug Stewart]

I an using qtoctave on windows xp
octave version 2.9.15

example that produces the problem:

residue([1],[ 1 10 25])

to fix the problem goto line 314 in residue
pnum = pnum + prepad (pn, N+1, 0);

and change it to

pnum = pnum + prepad (pn, N+1, 0,2);


This only shows up when it was trying to prepad a scaler and it padded 
it in the wrong direction.
By adding the 2 as the 4th parameter we tell it to pad in the right 
direction.


Sorry for the double posting but I saw that the line number was wrong 
because I still had my debugging lines in the code.

Doug Stewart