Add Observer. Remove functions from python side and add as observer of Problem. Add loads directions as functions. Minor changes.

Add formulation classes to build set of equations, and remove build methods from Element (flow only).
Draft methods to compute freestream velocity.
Rework data structure of boundary.
Add const.
Improve test cases.

Refactor normal computation to remove duplicated code.

New validated adjoint solver with gradients wrt to mesh and agnle of attack. Add mesh gradients computation in Element. Split run method in MshDeform. Minor changes.

Add automatic pin of a DOF if no Dirichlet BC is provided. Remove explicit Dirichlet, except in cylinder tests cases. Cleaning.

Add interface for linear sovlers. Add macros definition at global level. Adapt modules to test the different linear solvers.

Move Vector3d interface to tboxw.i. Replace Pt by Vector3d in heat, katropton, mirrors and sph + python files. Node.pos and Results remains

Added inlining for get methods in Element, Cache and Mem. Removed authorship in dox. Removed unused file.

Replaced std::vector by Eigen::Matrix in shape functions computations. Shape functions are now private and can be accessed by cache.get()

Replaced std::vector by std::deque to avoir size estimation when building list of triplet for sparse matrix

Changed assembly strategy for Kutta. Added internal Timers to flow. Changed verbosity (bool to int)).

Katropton: remove unused wMshConvert and add the possibility to read 1D point element with older gmsh versions