Add support for artificial viscosity to the 1d burgers scheme. - Add support for artificial viscosity by parametrizing the discretization operator and boundary closure on the viscosity. - Add a time stepper which evaluates and updates the residual viscosity of the solution.

function done = timeTask(taskName)
    fprintf('%s', taskName);
    tStart = tic;

    function done_fun()
        fprintf(' - done %fs\n', toc(tStart));
    end
    done = @done_fun;
end