Update v5.4.1 — Endless ATC Steam update #859607

Changelog for version 5.4.1, a small update: Added a hidden option to clear the plane tracks from the pause menu, by longpressing the 'text' button in the Display menu. Clearing tracks still happens automatically when resetting a game. A couple of adjustments and bug fixes to the new 'pilot error' function: fixed occasional 'say again' message when deselecting a plane, and pilots now always notify you in case of a possible miscommunication; this is to avoid confusion when values change. OK button text is now blue when a plane made a call. Added option to add QNH (altimeter) to the readbacks of planes that descend from a flight level to an altitude. It can be enabled by longpressing the 'readback' button in the Sound menu. In this sim, the QNH is a fixed value so this option affects readbacks only. It's off by default. For custom airports: small adjustment to the positioning of entry poin...