adjust calculateParabola for realisticAccuracy
Merge commit '3cfe2d107bd43fcd6124289cc0d0afc41e57bede' into realisticAccuracy
Revert "use realisticAccuracy only for linear trajectories"

This reverts commit 307930abb943311916069c84fc9d9360fb9bda80.
increase refDistance from 16 to 20
Use actual accuracy rather that accuracy/1.1

(so having >100% is meaningless, which makes sense because it is.)