Revert "Improved README file for display on GitHub and on the Doxygen documentation."

This reverts commit b42a5dbb87b597457af809f184b6d121ae2bf38b.
Revert "Improved automatically generated documentation."

This reverts commit 4d4f669e9d7172adaa723f32c63ca8c7c40abc12.
Revert "Renamed maillage.med to mesh.med."

This reverts commit fba3c476a38ff6fd49f91055f9b09a86bc09dbc5.