- 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
The following test cases:
- 04-JT60SA
- 05-JT60SA-startup
- 06-ITER-startup.Mixed
were affected by the bug fixed in f82f91bc, so their reference outputs
had to be updated.
1. Introduces enumerations (and some booleans) intended to replace all
the magic numbers used throughout the code to represent multiple
choices.
2. Replace the gray_params.sh script a new one that automatically
generates code for all the GRAY parameters by parsing
gray_params.f90.
3. Also generate extra code to accept the enum identifiers as valid
values in the configuration files and command line arguments.
4. Set sensible default values for parameters that are rarely changes.
