run/stop - Stop all button

[daitangio]

Provide a Stop All button
Long computation (like a function calling another function in graphing) can stuck the calculator.
Ypu are not able to turn it off either.
Pressing reset delete all the memory, so it is not a good option

Provide a stop button
One could implement it via a interrupt to stop the current computation and go to Home Screen, showing a message like
"Break requested!"

There is already some IRQ / NMI we can attach to?