Add utility for constructing the operators used by a discretization emplying RV-stabilization - Add constructDiffOps which creates the operatores used for a scheme with RV-stabilization - Minor clean up in RungekuttaExteriorRV

% Converts a gridfunction to a plot matrix
% Takes a grid function and and a structured grid.
function F = funcToPlotMatrix(g, gf)
    F = reshapeToPlotMatrix(gf, g.size());
end