Display rotation is relative to the scan order of the display.
The scan order can be found by scrolling the display with command
0x37 `display_bus.send(0x37, struct.pack(">H", i % 128))`
Fixes#1504
It's designed to minimize RAM footprint by using Sprites to
represent objects on the screen. The object model also facilitates
partial screen updating which reduces the bandwidth needed to display.
This is all handled in C. Python simply manipulates the objects with
the ability to synchronize to frame timing.
