navigator: removed "using" C++ directive
navigator: removed "using" C++ directive

There is only one occurence of the namespace specified,
so it's more readable to simply specify the full namespace in this case.

krbeverx/Firmware,dagar/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,dagar/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,PX4/Firmware,PX4/Firmware,acfloria/Firmware,acfloria/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,krbeverx/Firmware,dagar/Firmware,krbeverx/Firmware,dagar/Firmware,acfloria/Firmware,PX4/Firmware,dagar/Firmware,acfloria/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,PX4/Firmware,PX4/Firmware,dagar/Firmware,acfloria/Firmware,mje-nz/PX4-Firmware