Add gimbal to external control signal

Remove unnecessary AudioOutput dependencies.

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Move ArduPilot preflight check handling to generic QGC

http://www.wolframalpha.com/input/?i=!s+%7C%7C+(s+%26%26+a)Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Also hand carried text to speech changes from Stable to master. Plus
unit tests for that.

Some crazy shit in UAS.cc was using an array of 256 bytes to handle received messages and mapping them to components. Well, any message ID over 255 would cause a buffer overrun.

* Some code moved to Vehicle

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

This reverts commit ae976049ca7b4818616e6b8be07a028fc7dfc26f.