Merged in feature/dataspline (pull request #14) Feature/dataspline Approved-by: Jonatan Werpers <jonatan.werpers@it.uu.se> Approved-by: Martin Almquist <malmquist@stanford.edu>

function A = spdiag(a,i)
    default_arg('i',0);

    if isrow(a)
        a = a';
    end

    n = length(a)+abs(i);
    A = spdiags(a,i,n,n);
end