[Cleanup] Remove deprecated APIs (#529)

* Remove preferredFrameSize

* Remove -measure:

* Remove -measureWithSizeRange:

* Remove ASLayoutable

* Remove .name

* Remove deprecated style forwardings

That includes following properties that are declared on ASDisplayNode and ASLayoutSpec: spacingBefore, spacingAfter, flexGrow, flexShrink, flexBasis, alignSelf, ascender, descender, sizeRange and layoutPosition.

* Remove usesImplicitHierarchyManagement

* Remove deprecated range update callbacks:
-visibilityDidChange:
-visibleStateDidChange:
-displayStateDidChange:
-loadStateDidChange:

* Remove -clearFetchedData

* Remove -cancelLayoutTransitionsInProgress

* Remve ASDisplayNode+Deprecated.h

* Remove ASLayoutRangeTypeRender and ASLayoutRangeTypeFetchData

* Remove -[ASTableView clearContents]

* Remove reloadDataImmediately

* Remove ASStaticLayoutSpec

* Remove ASDimensionDeprecated

* Remove optional -pagerNode:constrainedSizeForNodeAtIndex: delegate method in ASPagerDelegate

* Remove suppressesInvalidCollectionUpdateExceptions

* Remove -[ASCollectionViewLayoutInspector initWithCollectionView]

* Remove ASVideoPlayerNode.loadAssetWhenNodeBecomesVisible

* Update CHANGELOG

* Update license of ASLayoutSpecTests.m

* Update examples/PagerNode

* Remove ASEnvironmentTraitCollection

* Remove -ASViewController.nodeConstrainedSize

* More on removing ASLayoutable

Source/ASCollectionView.h

@@ -280,14 +280,6 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)reloadData AS_UNAVAILABLE("Use ASCollectionNode method instead.");
 
-/**
- * Reload everything from scratch entirely on the main thread, destroying the working range and all cached nodes.
- *
- * @warning This method is substantially more expensive than UICollectionView's version and will block the main thread
- * while all the cells load.
- */
-- (void)reloadDataImmediately AS_UNAVAILABLE("Use ASCollectionNode method instead.");
-
 /**
  * Triggers a relayout of all nodes.
  *