autotest: fixed backup of autotest .bin logs
Plane: added DF logging of 2nd battery voltage
Replay: fixed build with AP_NavEKF API change
Copter: minor update to AC3.2-rc14 ReleaseNotes
Camera: Added feedback message support

Now the autopilot can publish the state of the camera via the mavlink_msg_camera_feedback message.
GCS_MAVLink: add CAMERA_FEEDBACK to enum
Copter: send a camera_feedback message when there is a camera trigger
Camera: record number of pictures taken since boot

The field is useful for detecting in a GCS if a mavlink_msg_camera_feedback message was dropped.
Copter: fix camera feedback msg handling

If the camera was disabled, camera message handling would fall though to
status-text msg handling.
Camera: initialise image_index
Camera: add f to float constants
AC_WPNav: Use target yaw instead of current yaw for close waypoints
Copter: supply wp_nav with attitude_control
Copter: rework control switch debouncing
Copter: add comments to control switch debouncing
Copter: re-order init_sonar

No functional change.
ArduPilot: update README.md
ArduPilot: fixup README format
AP_NavEKF : Improved Magnetometer Error Handling

(Plane Only) If the yaw and GPS heading disagree by more than 45 degrees on takeoff, then the magnetometer is declared as failed. The heading is then reset based on the difference between GPS ground track and stgate velocity vector.
Magnetometer fusion uses corrected data and bias states are initialised to zero. This allows the compass to be switched in flight.
For persistent compass errors that trigger a timeout, the compass is not permanently failed, however for non-forward fly vehicles the compass weighting is reduced.
AP_NavEKF: Clean up flight detector logic