Refactor new macOS code to reduce #ifs, increase shared code, and fix warnings

Limelight/Input/StreamView.h

@@ -6,8 +6,6 @@
 //  Copyright (c) 2014 Moonlight Stream. All rights reserved.
 //
 
-// This is redundant, as it is part of the prefix header
-//#import <UIKit/UIKit.h>
 #import "ControllerSupport.h"
 
 @protocol EdgeDetectionDelegate <NSObject>
@@ -16,7 +14,7 @@
 
 @end
 
-@interface StreamView : UIView
+@interface StreamView : OSView
 
 - (void) setupOnScreenControls:(ControllerSupport*)controllerSupport swipeDelegate:(id<EdgeDetectionDelegate>)swipeDelegate;
 - (void) setMouseDeltaFactors:(float)x y:(float)y;