/* Given the degree m and the m+1 complex coefficients a[0..m] of the polynomial sum(i=0,m){a[i]x^i},
and given a complex value x, this routine improves x by laguerre's method until it converges,
/* Given the degree m and the m+1 complex coefficients a[0..m] of the polynomial sum(i=0,m){a[i]x^i},
and given a complex value x, this routine improves x by laguerre's method until it converges,