Cleaning, fix tests

HySoP/hysop/domain/tests/test_obstacle.py

HySoP/hysop/gpu/gpu_transfer.py

HySoP/hysop/mpi/bridge_overlap.py

HySoP/hysop/mpi/tests/test_mesh.py

HySoP/hysop/mpi/topoOld

HySoP/hysop/operator/__init__.py

HySoP/hysop/operator/analytic.py

HySoP/hysop/operator/computational.py

HySoP/hysop/operator/redistribute.py

HySoP/hysop/operator/redistribute_inter.py

HySoP/hysop/operator/redistribute_intra.py

HySoP/hysop/operator/redistribute_overlap.py

HySoP/hysop/operator/tests/test_density.py

HySoP/hysop/operator/tests/test_redistribute.py

HySoP/hysop/operator/tests/test_reprojection.py

HySoP/hysop/problem/simulation.py

HySoP/hysop/test/__init__.py

HySoP/hysop/test/main_unit_tests.py

HySoP/hysop/test/test_obstacle/__init__.py

HySoP/hysop/test/test_obstacle/test_obstacle.py