Create residual viscosity package +rv and generalize the ResidualViscosity class - Generalize residual viscosity, by passing user-defined flux and calculating the time derivative outside of the update. - Create separate RungekuttaRV specifically using interior RV updates - Separate the artifical dissipation operator from the scheme AdvectionRV1D so that the same scheme can be reused for creating the diff op used by the ResidualViscosity class

function assertType(obj, type)
    if ~iscell(type)
        if ~isa(obj, type)
            error('sbplib:assertType:wrongType', '"%s" must have type "%s", found "%s"', inputname(1), type, class(obj));
        end
    else
        if ~isAnyOf(obj, type)
            error('sbplib:assertType:wrongType', '"%s" must be one of the types %s, found "%s"', inputname(1), toString(type), class(obj));
        end
    end
end