Save up to 94 bytes of RAM on 20x4 LCD Display machines (#6964)
* Save up to 94 bytes of RAM on 20x4 LCD Display machines
Moved the custom screen characters out of RAM into Program Memory. With
SD-Card support and the Progress Bar enabled, this saves 94 bytes of RAM
memory.
This was tested using the example_configurations/FolgerTech-i3-2020
files. So a couple small changes to those files snuck into this Pull
Request.
Probably... We can find similar savings in the Graphics LCD code it we
comb through it. And if so... That is the place we really need to
save RAM memory!
* Tidy up white space and indentation
The OLED is driven by an SSD1306, connected to the board via
I2C, the rotary encoder is connected to 3 GPIO pins.
Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>