In Curve: Added numerical FD differentiation if derivative is not supplied. Added arc length computation based on the derivative. Added arc length parameterization (but this function is very slow.). In +util: Added fzero_vec.m and integral_vec.m, which call fzero and integral but take vector arguments.

function l = point(p)
    l = line(p(1,:),p(2,:));
    l.LineStyle = 'none';
    l.Marker = '.';
end