Improve README #2
Description
Hopefully you still plan to work on ushell as it sounds like a cool concept, I've not been able to get it working yet.
The current ushell README is missing some important info currently. Adding something like this would help:
Run the build.sh script in the tests directory in the uShell repo to get a couple more demo programs to play around with, like the paint program. Copy `desktop.app` and the other .app files from this tests directory into a directory called ushell on your Uzebox SD card before loading ushell.uze.
ushell supports a PS/2 keyboard adapter attached to controller port 2 and a mouse attached to port 1.