Fix non-standard Fortran code
* Optional arguments in apply_operator were made non-optional, as optional arguments without explicit interface are disallowed. Those optional arguments were almost always supplied anyway when calling apply_operator. Without this fix, code could not work properly with pgfortran and nvfortran. * Argument list was incorrect when calling get_brak_hyper_parallel. Again, this works with some compilers because of the memory layout but it doesn't work with pgfortran.