Implemented RADIO_STATUS object and message handler

[mikerob]

I've had a crack at creating a new "radio_status" parameter and object that captures the MAVLINK RADIO_STATUS info.

mikerob@dbf311c

Really new at the whole Git thing, so not sure how to get it reviewed and rolled in.

[hamishwillee]

Hi @mikerob

Awesome - thanks very much!

With respect to contribution, check out this document. What it doesn't say is that we typically prefer a model where you branch off the main repository rather than creating a fork ... because that allows us to edit your work for issues more easily. Not needed for this one - but the best way to get it reviewed is to create a pull request back to master - we can then see that and comment.

I've created some comments inline on your changelist. In addition, minor point is to have fullstop at the end of the sentence (after values). You probably also need an empty line between these two linesfor the documentation to build properly.

    .. py:attribute:: radio_status
        :py:class: 'RadioStatus' rssi and noise values

The other thing that is missing is test code (this would catch some of the issues above). The document linked above explains our test options. A "quick and dirty test" for yourself for new messages is to update the vehicle_state.py example - if you can see the message working you know that the fundamentals are right!

Thanks!
H