Coupled Newton-Krylov iteration

[tbellosta]

I am interested in coupling the linear system solve for the different solvers in the RANS iteration as it may be able to give a sensible speed-up of the time-to-solution (for the Euler equations I am getting close to 10x speed-up).
Is anyone else interested / already working on it / want to collab?

[pcarruscag]

At this point: 8732e5d I had a coupled implementation, then I took it out and kept it only for fluid because the linear system was too difficult to solve.