[Table and collection views] Consider content inset when calculating (default) element size range (#525)

* Table and collection views to consider their content inset when calculating element size range

* Update CHANGELOG

* Address comments

* -[ASPagerNode currentPageIndex] to use pageSize instead of bounds

* Update documentation in ASPagerNode

* Minor change

Source/ASPagerNode.h

@@ -75,6 +75,9 @@ NS_ASSUME_NONNULL_BEGIN
 
 @end
 
+/**
+ * A horizontal, paging collection node.
+ */
 @interface ASPagerNode : ASCollectionNode
 
 /**
@@ -84,6 +87,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 /**
  * Initializer with custom-configured flow layout properties.
+ *
+ * NOTE: The flow layout must have a horizontal scroll direction.
  */
 - (instancetype)initWithCollectionViewLayout:(ASPagerFlowLayout *)flowLayout;