Added feature to change the up and the down positions of the penlift, and an extra command to set it.  C45,<down position>,<up position>,END will set the positions and save them into EEPROM.  The regular pen up and pen down commands have also been parameterised, so sending C14,180,END will set the pen up position to be 180, as well as actually move it there.  This will not otherwise save it to EEPROM, so can safely be used for testing without fear of wearing out that EEPROM address.