Merge latest master and update Layout headers

AsyncDisplayKit/ASViewController.h

@@ -9,11 +9,14 @@
 #import <UIKit/UIKit.h>
 #import <AsyncDisplayKit/ASDisplayNode.h>
 
+NS_ASSUME_NONNULL_BEGIN
+
 @interface ASViewController : UIViewController
 
 @property (nonatomic, strong, readonly) ASDisplayNode *node;
 
-//TODO Use nonnull annotation late on. Travis doesn't recognize it (yet).
 - (instancetype)initWithNode:(ASDisplayNode *)node;
 
 @end
+
+NS_ASSUME_NONNULL_END