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

% Plots all the eigen values for a sparse matrix.
function plotEig(A)
    e = eig(full(A));
    e = sort(e);
    plot(e,'.')
end