Added "fixture_label(obj)" helper to make diagnostics more useful.  Now that ids are generated randomly, printing out "observation #489872358" does us no good!  I couldn't figure out how to extract the label from the fixtures themselves, so I resorted to brute force and search the actual fixture file(!)
Added "fixture_label(obj)" helper to make diagnostics more useful.  Now that
ids are generated randomly, printing out "observation #489872358" does us no
good!  I couldn't figure out how to extract the label from the fixtures
themselves, so I resorted to brute force and search the actual fixture file(!)

pellaea/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,JoeCohen/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer