Update battery level to get better ADC results and convert the reported results to millivolts.  Results are now calibrated to within about 20mV when the voltage regulator is stable (battery level is above ~3.4V).
Change the bootloader is entered so that it is unlikely to happen by accident.  The kiss_poll_serial() function has been updated to require the 8-character sequence '<esc>S<esc>S<esc>S<esc>S' to be received while in WAIT_FOR_FEND state in order to enter the bootloader.  This sequence remains compatible with the avr109 bootloader code in avrdude and with the avr109 implementation in the Python-based Mobilinkd configuration utility.  The firmware will now respond with a '?' character for every 'S' character received in the above sequence.