Ardupilot udp serial port fix

[Williangalvani]

fix #2627

[joaoantoniocardoso]

nothing like a consistent API :)

[joaoantoniocardoso]

so, Ardupilot Manager here doesn't need to use the same description names as MAVLink endpoint types (see the class EndpointType above)?

[patrickelectric]

It appears that there is indeed an inconsistent as pointed by @joaoantoniocardoso

[Williangalvani]

so, Ardupilot Manager here doesn't need to use the same description names as MAVLink endpoint types (see the class EndpointType above)?

that is correct, these are not "Mavlink Endpoints". They are often not mavlink at all.

These are the serial port commandline arguments taken by ardupilot. which are [udp, udpin, tcp].
The ardupilot code could be updated to also take udpout, but that would only take effect in a future release.