Add general Runge-Kutta class - Add a general Runge-Kutta class which time integrates the solution based on coefficients obtained from a Butcher tableau - Add butcher tableau which returns coefficents for the specified Runge-Kutta method - Remove RungKutta4proper, since obsolete

function names = getVarname(varargin)
    names = cell(size(varargin));

    for i = 1:numel(varargin)
        names{i} = inputname(i);
    end
end