moving the preconditioner for Oseen into the linear solver (SolverTrilinos), commented the construction of precLin, preconditioner for the Jacobian system, that is not used

restyling HarmonicExtensionSolver: added the method applyBoundaryConditions(..), added the possibility to set an offset, as. The method updateDispDiff() was previously included in iterate()

moving the preconditioner to the class SolverTrilinos, the matrix on which we want to build the preconditioner is passed to solveSystem

Resolved with Gilles

Now corrected

In solveSystem, the linear system is set up with a given preconditioner,
it is solved, and (if retry = true) in case of non-convergence, the preconditioner is
recomputed. (cf doc in SolverTrilinos.hpp)

Also:
- changed cout in Display.leaderPrint.
- In Oseen the first resolution was done without preconditioner. Corrected.

changed width to  << setw(int).
removed close() at the end of the methods (the file is closed anyway, but I wonder why it is
not working with close() )

due to the change in PostProc method average, it is now mandatory to specify that average method will work on the finite element space "1" (being 0 - velocity feSpace, 1 - pressure feSpace)

moved default parameters from function definitions to function declarations (compatibility with intel c++ compiler)

+ the default "feSpace" parameter for "average" method is changed (0 instead of 1).

I have checked, but I will recheck after Paoloś commits

substituting the solveSystem with the one implemented on the SolverTrilinos, the leaderPrints with those of the class Displayer.

solveSystem is a method in SolverTrilinos thet can be shared among all the other solver. SolverTrilinos can be constructed passing the communicator, so that the output is printed only by proc 0.

fixed a bug that prevented compilation if some global variables where not defined previously, compilation of the manual should work fine now

There's a probleme with information transmition on the FS interface, reveting back to a working version in order to debug