mimics gauss function polymult
vecout=polymult(vec1,vec2)
vec1 = a (nx1) vector of coefficients representing a polynom
vec2 = a (mx1) vector of coefficients representing a polynom
vecout = a ((n+m)x1) vector of coefficients representing a polynom
polymult([1 2 1],[1 -2]) // returns //ans = //! 1. 0. - 3. - 2. !