Draft implementation of RungeKutta with exterior RV updates - Draft class RungeKuttaExteriorRV which updates the residual using a BDF approximation of the derivtive outside of the RK stages. - Draft class for BDF derivative

% 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