metadata: allow the user to specify XResolution/YResolution

see https://discuss.pixls.us/t/note-to-the-dev-guys-about-72-ppi-output

(cherry picked from commit ad237944699800368ba50151f6774ee203d61ed5)

rtgui/toolpanelcoord.h

@@ -348,6 +348,8 @@ public:
 
     void setEditProvider(EditDataProvider *provider);
 
+    void setProgressListener(rtengine::ProgressListener *pl);
+
 private:
     IdleRegister idle_register;
 };