* Refactor ASDataController
Check optional methods in ASDataControllerSource
* Reimplement reloadData
* Refactor new code
- No more new/inserted contexts flag
- Encapsulate code shared between reloadData and updateWithChangeSet
- Remove dataControllerWillDeleteAllData delegate method
- Hierarchy changes no longer needs to conform to NSCopying
- Reword TODOs
* Forgot to call completion block of reloadData :P
* Completion block of -[ASDataController reloadDataWithCompletion:] is nullable
* Data queried from ASCollectionNode and ASTableNode should be in UIKit index space
- This helps to avoid immature node allocation, especially when node virtualization is a thing
- However, this means that -reloadDataInitiallyIfNeeded in ASCollectionNode and ASTableNode must wait until all updates are finished.
* ASDataController shouldn't assume that allocated nodes were also laid out
* Revert "Data queried from ASCollectionNode and ASTableNode should be in UIKit index space"
This reverts commit 7bc977b3808a92f484b297781d0f5b30aa258e17.
* -nodeAtIndexPath: of ASDataController now forces node allocation, with the assumption that clients absolutely need it.
- Revisit this when node virtualization is implemented.
* ASDataController only grab changeSet.completionHandler when needed because it'll be niled out
* Fix ASTableViewTests related to reloadData
* Fix testThatDeletedItemsAreMarkedInvisible in ASCollectionViewTests
* Minor changes in ASCollectionView and ASTableView
* ASCollectionView and ASTableView shouldn't call [super reloadData] before their data controller does anything
* Address comments
* Fuse reloadData into -updateWithChangeSet: of ASDataController
* reloadData shouldn't be called as if it's inside a batch
- It can't be used in conjuntion with other updates.
- Calling it inside a batch update during the initial load can cause data inconsistency thrown by UICollectionView/UITableView
* Refactor ASDataControllerDelegate and ASRangeControllerDelegate
- Replace delegate methods in these protocols with -willUpdateWithChangeSet and -didUpdateWithChangeSet.
- ASRangeController, ASCollectionView and ASTableView are simplified because of this.
* Fix mismatch between sorting orders in ASDataController
* Forgot to call completion handler of reload change sets
* Make sure ASCollectionView is compatible with the behavior of UICollectionView's reloadData
- Since UICollectionView's reloadData doesn't requery data source but defers until the next layout pass, we need to wait until then to update range controller and do batch fetching.
- `-[ASCollectionView waitUntilAllUpdatesAreCommited]` needs to force a layout pass to make sure
everything is ready after it returns.
* testSectionIndexHandling of ASTableViewTests should only check visible nodes. Other nodes will be re-measured later.
* ASTableView is not ready until the first layout pass finished
* Address comments
* Bug fixes
* Start removing ASChangeSetDataController
* Continue removing ASChangeSetDataController
* Remove unnecessary change
* ASDataController is no longer an abstract class, remove its assertion
* Get back beginUpdates and endUpdatesAnimated:completion in ASCollectionNode
