cocoa: let the core handle key repeats

Report key down and key up modifiers to the core so that it can issue it's
own key repeats (instead of relying on Cocoa's ones).

osdep/macosx_application_objc.h

@@ -22,7 +22,7 @@
 
 @interface EventsResponder : NSObject <HIDRemoteDelegate>
 - (BOOL)handleMediaKey:(NSEvent *)event;
-- (NSEvent *)handleKeyDown:(NSEvent *)event;
+- (NSEvent *)handleKey:(NSEvent *)event;
 - (void)startAppleRemote;
 - (void)stopAppleRemote;
 - (void)startMediaKeys;