Added Pitch axis flipping. You must be pushing forward or back 3° to make it flip in Pitch axis or it will flip in the default roll axis.
Added some extra throttle control to maintain altitude
removed the CH7 ability to exit Flip mode. It will exit only if completing flip or user aborts with control sticks.
Previously flip relied on the attitude controller not updating the earth
frame target during the flip which can't be guaranteed. Safer for flip
to maintain it's own copy of the original attitude .
Jonathan Challinger
Robert Lefebvre
Randy Mackay
Jason Short