Add rotation to camera-based perspective tool

This rotation is different from the Rotate tool and the post-correction
adjustment rotation because it is applied between camera shift and
camera angle. It is equivalent to correcting the camera's roll and is
the same as the rotation calculated by automatic perspective correction.

rtengine/ashift_dt.c

@@ -670,7 +670,7 @@ static void homography(float *homograph, const float angle, const float shift_v,
 
   const float u = width;
   const float v = height;
-  const float rot = M_PI * angle / 180.0f;
+  const float rot = -M_PI * angle / 180.0f;
   const float pitch = M_PI * camera_pitch / 180.0f;
   const float yaw = M_PI * camera_yaw / 180.0f;