Display errors to users at conclusion of NEAT run

[caufieldjh]

NEAT runs may encounter a variety of caught errors and warnings:

• For sklearn: https://scikit-learn.org/stable/modules/classes.html#module-sklearn.exceptions
• For TF: https://www.tensorflow.org/api_docs/python/tf/errors

These should be presented to the user, perhaps through a ERROR.txt created in the same location as the final output (e.g., a graph_ml directory)

[justaddcoffee]

I'd advocate to make this file appear only when things go very wrong - e.g. a model doesn't converge and probably shouldn't be used