more helpful errors, to help end users
Created by: thopri
PyNEMO at the moment can return unhelpful error messages that don't help end user. E.g. for the benchmark test if ln_dyn_2d is set to true then PyNEMO will crash with an indexing error of an array.
This is due to their being no SSH data that PyNEMO is expecting. However it is not clear from the stack trace or log file that this is the problem.