Fix #5812
Show an error message when creating a KML without 2 items at least
Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Converted Structure Scan to use CameraCalc such that it now works with
camera specs.

Change from BATT_VOLT_PIN to BATT2_VOLT_PIN.
Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Also fixed bug with ArduPilot guided waypoint write which would trash
existing mission.

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

Handle survey mode state

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