gimbal v2 - note that FLAGS_YAW_LOCK is still valid

[hamishwillee]

This attempts to add the clarification in #531 (comment) that GIMBAL_DEVICE_FLAGS_YAW_LOCK can still be used when setting the gimbal attitude.

Look OK @julianoes ?

[rmackay9]

In addition to GIMBAL_DEVICE_SET_ATTITUDE, it should also be used in the MAV_CMD_DO_GIMBAL_MANAGER_PITCHYAW and GIMBAL_MANAGER_SET_PITCHYAW.

[hamishwillee]

Thanks @rmackay9 , but those use GIMBAL_MANAGER_FLAGS flags (same same name, but not the same thing)

[rmackay9]

ok. To be a bit nitpicky, it's not "target angles are relative to North", it is just "target yaw is relative to North". Target roll and pitch are always relative to the horizon I think.

EDIT: actually I guess we're just talking about set-attitude which always uses Quaternions..

[hamishwillee]

Be as nit picky as you can. This correct?

Suggested change

	> **Note** `GIMBAL_DEVICE_FLAGS_YAW_LOCK` must still be used when _setting_ an attitude target (in [GIMBAL_DEVICE_SET_ATTITUDE.flags](#GIMBAL_DEVICE_SET_ATTITUDE)), in order to specify that the target angles are relative to North.
	> **Note** `GIMBAL_DEVICE_FLAGS_YAW_LOCK` must still be used when _setting_ an attitude target (in [GIMBAL_DEVICE_SET_ATTITUDE.flags](#GIMBAL_DEVICE_SET_ATTITUDE)), in order to specify that the target yaw is relative to North.

[julianoes]

It applies to pitch/yaw as well as the quaternion.

[Davidsastresas]

Indeed. Maybe we should explicitly indicate this, somebody integrating a new gimbal in development, if not super familiarized with quaternions, could see really weird values on the angles and could not realize it is because of these flags being wrong.

[hamishwillee]

Add a github suggestion.