avoid autosizing depending on text content by returning an empty
preferredSize thus leaving all decisions to the layout manager
fix button grid specification
load 7seg font and test with altitude panel
disable dragging of statusbar
clarify cockpit partitioning
concrete implementation of altitude panel
energy panel
use GBL too to ensure same position as energy panel
fix minimal width of window to fit the number-panels
whitespace. i love whitespace.
start implementing status leds