Fixes from PR review including
(a) make some local variables const
(b) rename angle_max to veh_angle_max
(c) fix distance_to_lean_pct logic so distance of zero returns maximum lean angle
RC_Channel: To nullptr from NULL.
AC_Fence: To nullptr from NULL.
AC_Avoidance: To nullptr from NULL.
AC_PrecLand: To nullptr from NULL.
DataFlash: To nullptr from NULL.
SITL: To nullptr from NULL.
GCS_MAVLink: To nullptr from NULL.
DataFlash: To nullptr from NULL.
AP_Compass: To nullptr from NULL.
Global: To nullptr from NULL.
Global: To nullptr from NULL.
We should actually modify this function to scale back the z axis in order to avoid breaching the vertical fence. Currently breaching the vertical fence is handled within the position controller which is inconsistent.