Conjure: Consider adding Conjure object UUID for connecting objects that are generated from it

[rbyh]

A conjured Results object contains the original file columns as questions and answers.
The user has not necessarily also created an AgentList from the file, but should we provide an easy way to connect the results to the agent list that would be created -- eg a UUID for the Conjure object that is included in any agent list, survey or results that is generated from it (people may reuse the datafile_name)?

[johnjosephhorton]

So all coop-able objects now have a unique __hash__ identifier that is 19 digits. We could record these somewhere, though this seems like a meta-relationship task best suited for coop than making the objects "know" about this relationship. That being said, I was thinking about making __contains__ to capture ideas like a question being in a survey, a survey being in a results, an agent list being in results etc. so you could so stuff like:

>>> my_agent in my_cool_results 
True
>>> QuestionFreeText.example() in survey
False

is that agent was actually used in creating the results. Thoughts @apostolosfilippas and @rbyh ?