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.

rtgui/paramsedited.h

@@ -400,6 +400,7 @@ struct PerspectiveParamsEdited {
     bool camera_crop_factor;
     bool camera_focal_length;
     bool camera_pitch;
+    bool camera_roll;
     bool camera_shift_horiz;
     bool camera_shift_vert;
     bool camera_yaw;