Fixes compatibility for APM2. Also a significant update to the battery monitoring code: We previously had monitoring modes for individual cell voltages for 3 and 4 cell lipos. These have been removed as they were never really supported (the cell voltages were computed but were not reported or recorded anywhere). Also, some clean-up/prep work was done for supporting monitoring 2 separate battery packs. The CLI battery and current monitoring tests were consolidated into 1 test.
