Add BG accel to BG delta list (copy from AutoISF to main build)

[MowgliChild]

Functional improvement request: Add BG acc to main build

BG accel is displayed in AutoISF on top of the 3 normal deltas and used for various functions within this dev branch.

This is an excellent tool for seeing what is happening in real time, the code already exists and the real estate is already there on the Home Screen. Not a request for doing something with the accel, but just to display it. :)