test in synthetic for analytics new features
mockup for incremental inference with analytics. need to have observe_from_file return the observe as a string so we can update analytics object using it. note the awkward thign that we now have various functions specialized to the venture unit object (which has various attributes that we use). on the other hand, should be easy enough to just pass round two objects, and sometimes work on unit and sometimes on analytics. the only really dynamic thing is the ripl, which is updating due to inference.