fzero_vec, integral_vec and spline are now local functions in Curve. Renamed arcLengthStretch to arcLengthParametrization. Removed plot_derivative. Added some comments and extra lines + removed unneccesary lines. arcLength is now a method and not static. Constructor does not accept difference operator anymore.

function x = gridVector1d(schms)
    n = length(schms);
    x = cell(n,1);

    for i = 1:n
        x{i} = schms{i}.x;
    end
end