Merge branch 'master' into update-objc

Conflicts:
	AsyncDisplayKit/Details/UIView+ASConvenience.h

AsyncDisplayKit/ASTableView.h

@@ -261,6 +261,20 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property (nonatomic) BOOL automaticallyAdjustsContentOffset;
 
+/**
+ * Triggers all loaded ASCellNodes to destroy displayed contents (freeing a lot of memory).
+ *
+ * @discussion This method should only be called by ASTableNode.  To be removed in a later release.
+ */
+- (void)clearContents;
+
+/**
+ * Triggers all loaded ASCellNodes to purge any data fetched from the network or disk (freeing memory).
+ *
+ * @discussion This method should only be called by ASTableNode.  To be removed in a later release.
+ */
+- (void)clearFetchedData;
+
 @end