Vandermonde matrix, vander() function extension

Adds functionality to the original MATLAB vander() function.

Uses the more common definition of the Vandermonde matrix with power zero to the left, and adds the ability to create non-square matrices for more flexibility.

V=vander2(v,k)=[v.^0 v.^1 ... v.^k];
where length(v)=n and dim(V)=[n, k].

Note that replacing the original vander() function can cause other functions to fail.