Kepler

Even in 'relaxed' kar opening mode, you have to use the 'force open' option to open kars saved beneath 2.1 (2.0 kars are ok, because module dependencies weren't properly recorded in 2.0, so I think they're always openable-without-a-warning when in 'relaxed). I imagine this is because the ptolemy module changed names to ptolemy-kepler, so the modules dependency checking code can't tell that ptolemy and ptolemy-kepler are the "same" module, and thus thinks a module is missing, prompting you to either restart with the proper modules, or attempt a force open.