Improve error handling for Python library

[nedtaylor]

The Python library (notebook kernels mainly) does not handle Fortran stops and exits well. Additionally, the code should not stop, it should instead return an error to Python so that the user can continue.

Files

• src/fortran/lib/mod_cache.f90
• src/fortran/lib/mod_generator.f90
• src/fortran/lib/mod_geom_rw.f90
• src/fortran/lib/mod_geom_utils.f90
• src/fortran/lib/mod_help.f90
• src/fortran/lib/mod_intf_identifier.f90
• src/fortran/lib/mod_io_utils.F90
• src/fortran/lib/mod_io_utils_extd.F90
• src/fortran/lib/mod_lat_compare.f90
• src/fortran/lib/mod_misc.f90
• src/fortran/lib/mod_misc_linalg.f90
• src/fortran/lib/mod_misc_maths.f90
• src/fortran/lib/mod_misc_types.f90
• src/fortran/lib/mod_plane_matching.f90
• src/fortran/lib/mod_shifting.f90
• src/fortran/lib/mod_swapping.f90
• src/fortran/lib/mod_sym.f90
• src/fortran/lib/mod_terminations.f90
• src/fortran/artemis.f90