Remove unused headers (#1358)

Summary:
###  Changes in this pull request

* Improve compilation time by reducing unnecessary compilation dependencies
* More clean code

### Checklist

- [x] All tests pass. Demo project builds and runs.
- [x] I added tests, an experiment, or detailed why my change isn't tested.
- [x] I added an entry to the `CHANGELOG.md` for any breaking changes, enhancements, or bug fixes.
- [x] I have reviewed the [contributing guide](https://github.com/Instagram/IGListKit/blob/master/.github/CONTRIBUTING.md)
Pull Request resolved: https://github.com/Instagram/IGListKit/pull/1358

Differential Revision: D17200761

Pulled By: lorixx

fbshipit-source-id: 9c6bca4d3d5e2e4b35125c7a12e483d58993c4e8

Source/Common/IGListDiff.mm

@@ -12,7 +12,6 @@
 #import <vector>
 
 #import <IGListKit/IGListCompatibility.h>
-#import <IGListKit/IGListMacros.h>
 #import <IGListKit/IGListExperiments.h>
 
 #import "IGListIndexPathResultInternal.h"

Source/Common/IGListIndexSetResult.m

@@ -8,8 +8,6 @@
 #import "IGListIndexSetResult.h"
 #import "IGListIndexSetResultInternal.h"
 
-#import <IGListKit/IGListMoveIndex.h>
-
 @implementation IGListIndexSetResult {
     NSMapTable<id<NSObject>, NSNumber *> *_oldIndexMap;
     NSMapTable<id<NSObject>, NSNumber *> *_newIndexMap;

Source/Common/IGListMoveIndex.m

@@ -6,7 +6,6 @@
  */
 
 #import "IGListMoveIndex.h"
-#import "IGListMoveIndexInternal.h"
 
 @implementation IGListMoveIndex
 

Source/Common/IGListMoveIndexPath.m

@@ -6,9 +6,6 @@
  */
 
 #import "IGListMoveIndexPath.h"
-#import "IGListMoveIndexPathInternal.h"
-
-#import <IGListKit/IGListMacros.h>
 
 @implementation IGListMoveIndexPath
 

Source/IGListAdapterUpdater.m

@@ -9,8 +9,6 @@
 #import "IGListAdapterUpdaterInternal.h"
 
 #import <IGListKit/IGListAssert.h>
-#import <IGListKit/IGListBatchUpdateData.h>
-#import <IGListKit/IGListDiff.h>
 #import <IGListKit/IGListIndexSetResultInternal.h>
 #import <IGListKit/IGListMoveIndexPathInternal.h>
 

Source/IGListBindingSectionController.m

@@ -8,10 +8,7 @@
 #import "IGListBindingSectionController.h"
 
 #import <IGListKit/IGListAssert.h>
-#import <IGListKit/IGListDiffable.h>
-#import <IGListKit/IGListDiff.h>
 #import <IGListKit/IGListBindable.h>
-#import <IGListKit/IGListAdapterUpdater.h>
 
 #import "IGListArrayUtilsInternal.h"
 

Source/IGListStackedSectionController.m

@@ -10,7 +10,6 @@
 #import <objc/runtime.h>
 
 #import <IGListKit/IGListAssert.h>
-#import <IGListKit/IGListSupplementaryViewSource.h>
 
 #import "IGListSectionControllerInternal.h"
 

Source/Internal/IGListAdapter+UICollectionView.m

@@ -11,7 +11,6 @@
 #import <IGListKit/IGListAssert.h>
 #import <IGListKit/IGListSectionController.h>
 #import <IGListKit/IGListSectionControllerInternal.h>
-#import <IGListKit/UICollectionViewLayout+InteractiveReordering.h>
 
 @implementation IGListAdapter (UICollectionView)
 

Source/Internal/IGListDebugger.m

@@ -7,7 +7,6 @@
 
 #import "IGListDebugger.h"
 
-#import "IGListDebuggingUtilities.h"
 #import "IGListAdapter+DebugDescription.h"
 
 @implementation IGListDebugger

Source/Internal/IGListWorkingRangeHandler.mm

@@ -9,14 +9,10 @@
 
 #import <set>
 #import <unordered_set>
-#import <vector>
 
 #import <IGListKit/IGListAssert.h>
 #import <IGListKit/IGListAdapter.h>
 #import <IGListKit/IGListSectionController.h>
-#import <IGListKit/IGListWorkingRangeDelegate.h>
-
-#import "IGListWorkingRangeDelegate.h"
 
 struct _IGListWorkingRangeHandlerIndexPath {
     NSInteger section;

Source/Internal/UICollectionViewLayout+InteractiveReordering.m

@@ -7,9 +7,7 @@
 
 #import "UICollectionViewLayout+InteractiveReordering.h"
 
-#import <IGListKit/IGListAdapterDataSource.h>
 #import <IGListKit/IGListAdapterInternal.h>
-#import <IGListKit/IGListAssert.h>
 #import <IGListKit/IGListSectionController.h>
 #import <IGListKit/IGSystemVersion.h>