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 [x,y] = gridVector2d(schms)
    n = length(schms);
    x = cell(n,1);
    y = cell(n,1);

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