Added adjoint for AoA and mesh in 2D. Nodes indices are now passed to the BoundaryLayer object

Adjoint is not working because the delta star box is missing

Boundary layer c++ objects are created in python with swig and are manipulated by the interface. The initial condition of the viscous solver was changed. All test cases have been adapted. A decrease in the number of iterations is globally observed. Results are slightly improved especially for the RAE validation case.

Contains 2D and 3D developements as well as the api.