AP_AHRS_View: add method to get pitch trim and note on rotation

libraries/AP_AHRS/AP_AHRS_View.h

@@ -187,10 +187,14 @@ public:
 
 
     // get current rotation
+    // note that this may not be the rotation were actually using, see _pitch_trim_deg
     enum Rotation get_rotation(void) const {
         return rotation;
     }
 
+    // get pitch trim (deg)
+    float get_pitch_trim() const { return _pitch_trim_deg; }
+
 private:
     const enum Rotation rotation;
     AP_AHRS &ahrs;