VLCKit: fix examples compiler warnings

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

Examples_iOS/DropIn-Player/Dropin-Player/VDLPlaybackViewController.m

@@ -26,7 +26,7 @@
 #import "VDLPlaybackViewController.h"
 #import <AVFoundation/AVFoundation.h>
 
-@interface VDLPlaybackViewController () <UIGestureRecognizerDelegate, UIActionSheetDelegate>
+@interface VDLPlaybackViewController () <UIGestureRecognizerDelegate, UIActionSheetDelegate, VLCMediaPlayerDelegate>
 {
     VLCMediaPlayer *_mediaplayer;
     BOOL _setPosition;

Examples_iOS/SimplePlayback/SimplePlayback/VDLViewController.m

@@ -25,7 +25,7 @@
 
 #import "VDLViewController.h"
 
-@interface VDLViewController ()
+@interface VDLViewController () <VLCMediaPlayerDelegate>
 {
     VLCMediaPlayer *_mediaplayer;
 }