Improve the explanation below the app

[moorepants]

Andrew Dressel had this comment:

"Will you implement some kind of "About" or "Help" functionality in the UI? For example, How it steer axis tilt measured? It certainly is discoverable, especially if you switch to degrees, but some users, especially the old ones, might prefer just to read it explicitly."

We need to explain the parameters and the outputs more carefully so the app is self contained.