Fourth-order correction for cumulants
Adds the fourth-order diffusion correction to the D3Q27 cumulants, as proposed in Geier et al. (2017). Also adds the possibility to use limiters for the third-order cumulants in order to increase stability.
This MR depends on the MR pystencils!338 (merged) and can only be merged afterwards.
Edited by Helen Schottenhamml