Moving source files into Vehicles as it is a more coherent place.

Forcing QGC to use Mavlink V2 if vehicle supports it.

_finalize methods need information which is not available if all you
have is a mavlink_message_t

This reverts commit ae976049ca7b4818616e6b8be07a028fc7dfc26f.

This way we don't need macro-magic to deal with
different operating systems and compilers.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

Removed incorrect Vehicle.altitudeWGS84