Add command line option to save state to YAML by default in case of failure

[lcjohnso]

For use in the case of scripting multiple iterations of a panoptes command (e.g., for uploading multiple batches of subjects), the ability to automatically save state to a YAML file as an option flag has been requested. This new feature would allow a loop with multiple iterations of the panoptes command to continue without the need for interactive feedback in the form of a Y/N response regarding the user's preference to save (or not) the state of execution to a YAML file in the case of a failure or error.

Recommendation: including the -s --save-to-yaml option would automatically save state to YAML in case of a failure.