This reverts commit 52160d80.

Pulling mavlink with a reversal for the CAMERA_IMAGE_CAPTURED message. It's now back as it was so it won't break existing code.
The pull also brought changes to the GPS_RAW_INT message. Only MockLink uses. I entered zeros for all new fields.

Prevent shutdown ordering crashes

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

- Now responds to request_list using a worker routine to send out
params one at a time
- Support for failure modes for unit testing

- Delay gps position for better testing
- Longer delay on home position

This mechanism automatically queues data into the correct thread where necessary, otherwise the method is invoked directly with low overhead.

At the same time remove the UDP socket event workaround. It is not a problem.

Plus other auto connect bug fixes