equalizer: privatize slider include

Sources/VLCEqualizerView.h

@@ -12,7 +12,6 @@
 
 #import <UIKit/UIKit.h>
 #import "VLCFrostedGlasView.h"
-#import "VLCSlider.h"
 
 @protocol VLCEqualizerViewDelegate <NSObject>
 

Sources/VLCEqualizerView.m

@@ -15,6 +15,7 @@
 #import "VLCTrackSelectorTableViewCell.h"
 #import "VLCTrackSelectorHeaderView.h"
 #import "UIDevice+VLC.h"
+#import "VLCSlider.h"
 
 #define PROFILE_SELECTOR_TABLEVIEW_SECTIONHEADER @"profile selector table section header"
 #define PROFILE_SELECTOR_TABLEVIEW_CELL @"profile selector table view cell"

Sources/VLCMovieViewController.m

@@ -33,6 +33,7 @@
 #import "VLCAppDelegate.h"
 #import "VLCStatusLabel.h"
 #import "VLCMovieViewControlPanelViewController.h"
+#import "VLCSlider.h"
 
 #define FORWARD_SWIPE_DURATION 30
 #define BACKWARD_SWIPE_DURATION 10