Add OLED support over bluetooth.

Example usage:
 i4oled -d /sys/class/hidraw/hidraw0/device/oled5_img -t "Alt+Ctrl" -b

 i4oled -d /sys/class/hidraw/hidraw0/device/oled7_img -i help.png -b

Text is rendered to 1-bit, currently using DejaVu font.

Images are rendered to 1-bit without dithering.

Signed-off-by: Przemo Firszt <przemo@firszt.eu>
Version 1.1