Implement 4-Wire SPI for SSD1306

[ikskuh]

[mattnite]

@ikskuh please link datasheet

[ikskuh]

The datasheet is linked in the source code, and most stuff is already implemented. We're blocking on the writev refactoring which i'm currently on.

Afterwards, it shouldn't be that hard to implement as in theory, it's "just" removing the i2c prefix in all commands

[Grazfather]

Was this completed with #246?