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.

% Calculates M so that the stepsize m/M is as close to n/M as possible
function M = equal_step_size(n,N,m)
    M = round((m*(N-1)+n)/n);
end