Bugfix header EEPROM layout: Batterycharge was added to the header memory structure which is also used to store data in EEPROM => Information read from EEPROM which were created before the change was not read out correct. To avoid this problem and to keep the layout consistent a not used data item has been changed to the new batterycharge value

Imported from Ac6/SystemWorkbench/plugins/fr.ac6.mcu.firmware_1.14.7.201711101414/resources/builtin/:
* File syscalls.c