Changes

Clubb ticket #1025: Implemented way to make esa tuner reproducible, h… (#1068)

* Clubb ticket #1025: Implemented way to make esa tuner reproducible, hid error output of optional diagnostic variables behind check, fixed parallelization issue with tuner, esa max_iters parameter is now in stats namelist, fixed issue with TUNER compiler directive, some small fixes.
- New namelist variables prescribed_rand_seed and l_use_prescribed_rand_seed determine if the esa tuner will use a random or a fixed value as random seed. Added descriptions to README.
- Added max_iters to stats namelist to make it more modifiable.
- Renamed stp_adjst_intercept_in and stp_adjst_slope_in to stp_adjst_shift_in and stp_adjst_factor_in, respectively, to better reflect their influence on step size.
- The error output in src/CLUBB_core/pdf_closure_module.F90 for the diagnostic variables wprtp2, wpthlp2, wprtpthlp, and rcp2 is now hidden behind existence checks for these variables. And a clarification was added to "#ifdef TUNER" directive.
- NetCDF file access caused the tuner to crash in parallel mode (-fopenmp flag in config file and multiple cases). Adding an $OMP CRITICAL structure around the call to stats_init in clubb_driver.F90 fixed that.
- Fixed compile/README. Config files are specified with the -c option.
- The -t option in run_scripts/run_tuner.bash interfered with the previous usage of the TUNER compiler directive. Renamed the old TUNER directive to NR_SP, a short for "numerical recipes, single precision". TUNER now is the option to "turn on" code changes required to run the tuner.