- Avoid logging the same error over and over
- Make all the gray_errors actually warnings
- Replace `large_npl` error with `unstable_beam`, which is actually
the root cause of the former
- Use the gray_main error as exit code
This change replaces the output files (Fortran units) with a derived
type called table, that hold the data in memory until further
processing. The data stored in a table can be dumped to a file, as
before, or processed in other ways, for example converted to other
derived type.
This adds a new configuration file based on the INI format.
The new format will allow adding GRAY parameters without breaking
compatibility with existing configurations, unlike as of the old
gray_params.data.
