* Added a member to `ASTextKitAttributes` that is an optional delegate to the struct's NSLayoutManager.
* Changed ASTextNode to set this delegate to an instance of ASTextNodeWordKerner.
* Updated init method of `ASTextKitContext` to take an optional NSLayoutManager delegate
* Added the files in TextKit folder to the public headers (so we can include ASTextNodeTypes.h)
- Cell node automatically notifies the delegate after a relayout (via -setNeedsLayout) that results in a new size. Confirming to ASCellNodeDelegate; ASTableView and ASCollectionView reload the calling cell upon notifications. These views automatically set themselves as delegate of every node.
- The result is that ASCellNode subclasses don't need to manually notify the containing view. Thus, `-relayoutItemAtIndexPath` and `-relayoutRowAtIndexPath` are removed.
- Kittens example is updated to reflect the change.
ASNetworkImageNode defers to ASImageNode to return its calculatedSize. ASImageNode returns the size of its image. There is a good chance that ASNetworkImageNode hasn't downloaded its image yet when calculatedSize is called, so it returns a size of CGSizeZero.
On top of that, it is possible that the size of the image is not actually the size that we wish to display in our node.
I've added an "expectedImageSize" property that can be used to determine the calculatedSize of an ASNetworkImageNode.
- ASLayoutable requires mutable properties that are used when attached to a stack layout.
- Thus, ASLayoutable objects (including ASDisplayNode) can be injected into stack layout directly.
- ASStackLayoutNodeChild no longer needed.
- Tests and Kitten sample updated.
- Both ASDisplayNode and ASLayoutNode conforms to this protocol.
- ASDisplayNode can be embeded directly into layout graph.
- Eliminate ASCompositeNode.
- Fix ASStaticSizeDisplayNode not recpect min constrained size.
- Updated tests.
