Further reduction of include dependencies

rtengine/imageio.h

@@ -29,8 +29,6 @@
 #include "imageformat.h"
 #include "rtengine.h"
 
-#include "../rtexif/rtexif.h"
-
 enum {
     IMIO_SUCCESS,
     IMIO_CANNOTREADFILE,
@@ -42,6 +40,13 @@ enum {
     IMIO_CANNOTWRITEFILE
 };
 
+namespace rtexif
+{
+
+class TagDirectory;
+
+}
+
 namespace rtengine
 {
 
@@ -49,6 +54,13 @@ class ColorTemp;
 class ProgressListener;
 class Imagefloat;
 
+namespace procparams
+{
+
+class ExifPairs;
+
+}
+
 class ImageIO : virtual public ImageDatas
 {