Work log - 3/23

I've added a full, real diagnostic chart to the database.  It guides a person through trying to diagnose why a car won't start.  It has a whopping 33 nodes/QuestionStates in it.  I'm planning on having at least one more done by our client meeting on Wednesday, maybe two.  I also spent some time today and yesterday updating the data model documentation and the implementation of it.  In particular, I added stuff so that when a user selects a symptom to diagnose, the program will pick the most likely entry point into a diagnostic point if there are multiple places to start.  Unfortunately, some of these changes affected other code which has to be (lightly) refactored in a couple places, and also made some of my unit tests either not work or no longer constitute a valid test of correct behavior.