Dennis Gläser authored Oct 19, 2016 and Timo Koch committed Nov 23, 2016

Updating the flux var cache is very expensive for mpfa schemes.
We thus introduce a new update() method in the elementfluxvarcaches.
Instead of binding again, the localjacobian calls this method. In the
tpfa case this forwards directly to bind when parameters are solution dependent
as we know we only store the darcy transmissibilities as the others are by default
solution dependent and are calculated on the fly. For mpfa, the fluxvarcachefiller
decides what to update (in case of compositional flow only the diffusive transmissibilities
will be updated when the permeability is not solution dependent).