backlight handling: Previously if keypad=yes was configured in LCDd.conf a value for the backlight was sent, regardless of the configuration in hd44780-serial.c. Now it decides upon the backlight flag from that file (enabling it in LCDd.conf is still required). If the backlight flag indicates the device supports backlight, the backlight_on / backlight_off values are sent (even if they are 0x00)!