Surface: Made "raw" field private.

I cheated a bit by declaring ASFont as friend, but all other outside
access now happens via methods.

I removed the "saveScreenshot" method since the code calling it is
commented out and I never heard anyone complain about missing this
feature.

src/gmenu2x.h

@@ -210,7 +210,6 @@ public:
 	void viewLog();
 	void contextMenu();
 	void changeWallpaper();
-	void saveScreenshot();
 
 	void applyRamTimings();
 	void applyDefaultTimings();