Always evaluated to false due to signed/unsigned

- NAN not available in windows headers, use cross platform friendly
version
- VS compiler does not allow initializing non-integral types in header
files
- ActiveQt libs are already installed by Win Qt4.8.5, no need to build.
Plus this part of the makefile just loops without nmake.exe installed
which is not part of a standard windows box

Altitude splitted to altitudeAMSL and altitudeRelative, speed splitted to airSpeed and groundSpeed. PrimaryFlightDisplay uses airSpeed for FW and groundSpeed for MC.

flightgear hil: correct scaling of pressure for mavlink message and remove indicated airspeed from flightgear protocol, commit requires flightgear protocol update

This commit disabled RC RAW signal callback.