ENH: Easy version parsing

Ready for review/merge @drammock or @rkmaddox. Realized it's nice to have this to know which version is currently checked out when finalizing an experiment.
True. Right now the check is automatically handled in the stamp functions since they naturally iterate (and iterating over an empty list does nothing). Subsequent PR welcome if you want to unify it to skip in `_experiment_controller.py` since it is a little bit cleaner.