Another day, another update.

And I haven't even had the time to play with the lyrics viewer
But I did pull a bunch of long overdue updates together and tested the result lightly.

The important changes are
- popups now work as I intended them to
- the negative altitude bug is fixed
- the code should track our current position in a route a bit better now
- if gpsd is available, connect to that instead of the serial port
- when a user is flipping through the waypoints with the knob, wait 10 seconds before we restart the automatic tracking of our position