The new led font is now antialiased (`a la Andy) and has

The new led font is now antialiased (`a la Andy) and has
twice the design size (character height) of the old one.
Advantages:
- displays . and : correctly with less space around, and digits
  with more space around (using Andy's improvements to plib)
- small text becomes much more legible (-> clock, AP-altitude)
- the font contains pretty much every character that can be
  displayed on a seven segment display, so it might be more
  useful for future instruments.