Allow for the residual normalization function to return a vector. Also change the default normalization from normalizing on norm(u-mean(u),inf) to norm(u/2), since this proved to be better for 1d burgers

function y = rickerWavelet(x, x0, A)
    y = (1-2*pi^2*A^2*(x-x0).^2).*exp(-pi^2*A^2*(x-x0).^2);
end