Round instead of flooring range-ticks on HSI.
Move source docs to src/.
Fix Lookahead module to use Module::update_dt().
Remove showing FPS by EFISWidget.
Make possible to disable module by adding "disabled='true'" in XML.
Support painting control stick position on EFIS.
FBW systems: APMultiplexer and Stabilizer.

Also add output support to the FlightGearIO module.
Still need to fix some things, and implement value winding
in PID.