Some users may prefer to hide the position updates on the `LIGHTWEIGHT_UI` altogether. This leads to an even less cluttered display (it also saves on SPI traffic and one byte of RAM).

- Show units on lightweight status screen.
- Fixed progress bar so it works with M73

- This status screen uses the ST7920 character generator to greatly
  reduce SPI traffic and MCU load when updating the status screen.

- Has been tested with the RepRapDiscount Full Graphics Smart Controller
  but should work with any LCD that uses an ST7920 or fully compatible
  controller.

- This makes it look less like a dash (idea stolen from cjsoong).

- This will slightly reduce the SPI requirements for
  updating the progress bar.

- Also deleted old implementation files which had been renamed.

- The status screen uses the ST7920 character generator to greatly
  reduce SPI traffic and MCU load when updating the status screen.

- Has been tested with the RepRapDiscount Full Graphics Smart Controller
  but should work with any LCD that uses an ST7920 or fully compatible
  controller.

- avr-gcc is more strict than the Arduino IDE, it seems.