implement window position save and restore in OSX

PanoPainter/GameViewController.m

@@ -10,6 +10,7 @@
 #import "GameViewController.h"
 #import <OpenGLES/ES3/glext.h>
 #include "app.h"
+#include "settings.h"
 #import "objc_utils.h"
 
 std::mutex render_mutex;
@@ -433,7 +434,8 @@ std::set<UITouch*> ignored_touch;
 
     App::I->width = view.frame.size.width * view.contentScaleFactor;
     App::I->height = view.frame.size.height * view.contentScaleFactor;
-    
+    App::I->zoom = Settings::value_or<Serializer::Float>("ui-scale", (float)view.contentScaleFactor);
+
     App::I->render_thread_start();
     App::I->ui_thread_start();
 }