References
----------
- https://learn.adafruit.com/monochrome-oled-breakouts
- https://github.com/adafruit/Adafruit_Python_SSD1306
- http://www.dafont.com/bitmap.php
- http://raspberrypi.znix.com/hipidocs/topic_i2cbus_2.htm
- http://martin-jones.com/2013/08/20/how-to-get-the-second-raspberry-pi-i2c-bus-to-work/
- https://projects.drogon.net/understanding-spi-on-the-raspberry-pi/
- https://pinout.xyz/
- https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi
- http://code.activestate.com/recipes/577187-python-thread-pool/
- https://www.circuits.dk/everything-about-raspberry-gpio/
