Merge branch 'master' of https://gitlab.onelab.info/gmsh/fwi

CMakeLists.txt

common/configuration.cpp

common/configuration.h

common/data/element.h

common/model/parametrization.h

common/model/updater.cpp

common/statefunctional.cpp

common/statefunctional.h

common/wave/element.cpp

common/wave/element.h

common/wave/equation/equation.cpp

convergence.cpp

directional.cpp

directional_field.cpp

error.cpp

gradient.cpp

inversion.cpp

ip_comparison.cpp

multiscale.cpp

ob_comparison.cpp