Bugfix Curve.arcLengthParametrization() by using linear interpolation instead of higher-order spline for parameter as a funciton of arclength. Generalize dataSpline() to curves in higher dimensions.

% Get the index of the points p within the tall array of points ps
function [I, ok] = pointIndex(p, ps)
    [ok, I] = ismember(p,  ps, 'rows');
end