Remove refs to IGListSectionType, fix TV app example

Summary:
- Clean up docs
  - Remove `IGListSectionType` and `IGListCollectionView`
- Fix TV app example

Issue fixed: #675

- [x] All tests pass. Demo project builds and runs.
Closes https://github.com/Instagram/IGListKit/pull/676

Differential Revision: D4915634

Pulled By: rnystrom

fbshipit-source-id: 60eb1f1e5ece7fe68f6bf44b465bd5379615d716

Examples/Examples-tvOS/IGListKitExamples/SectionControllers/CarouselSectionController.swift

@@ -15,7 +15,7 @@
 import UIKit
 import IGListKit
 
-final class CarouselSectionController: IGListSectionController, IGListSectionType {
+final class CarouselSectionController: IGListSectionController {
 
     var number: Int?
     
@@ -24,11 +24,11 @@ final class CarouselSectionController: IGListSectionController, IGListSectionTyp
         self.inset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 10)
     }
     
-    func numberOfItems() -> Int {
+    override func numberOfItems() -> Int {
         return 1
     }
     
-    func sizeForItem(at index: Int) -> CGSize {
+    override func sizeForItem(at index: Int) -> CGSize {
         let height = collectionContext?.containerSize.height ?? 0
         let aspectRatio: CGFloat = 0.75 // 3:4
         let width = height * aspectRatio
@@ -36,17 +36,17 @@ final class CarouselSectionController: IGListSectionController, IGListSectionTyp
         return CGSize(width: width, height: height)
     }
     
-    func cellForItem(at index: Int) -> UICollectionViewCell {
+    override func cellForItem(at index: Int) -> UICollectionViewCell {
         let cell = collectionContext!.dequeueReusableCell(withNibName: "CarouselCell", bundle: nil, for: self, at: index) as! CarouselCell
         let value = number ?? 0
         cell.titleLabel.text = "#\(value + 1)"
         return cell
     }
     
-    func didUpdate(to object: Any) {
+    override func didUpdate(to object: Any) {
         number = object as? Int
     }
     
-    func didSelectItem(at index: Int) {}
+    override func didSelectItem(at index: Int) {}
     
 }

Examples/Examples-tvOS/IGListKitExamples/SectionControllers/DemoSectionController.swift

@@ -31,7 +31,7 @@ final class DemoItem: NSObject {
     
 }
 
-final class DemoSectionController: IGListSectionController, IGListSectionType {
+final class DemoSectionController: IGListSectionController {
 
     var object: DemoItem?
     
@@ -40,26 +40,26 @@ final class DemoSectionController: IGListSectionController, IGListSectionType {
         inset = UIEdgeInsets(top: 0, left: 50, bottom: 10, right: 0)
     }
     
-    func numberOfItems() -> Int {
+    override func numberOfItems() -> Int {
         return 1
     }
     
-    func sizeForItem(at index: Int) -> CGSize {
+    override func sizeForItem(at index: Int) -> CGSize {
         let itemWidth = (collectionContext!.containerSize.width / 2) - inset.left
         return CGSize(width: itemWidth, height: 100)
     }
     
-    func cellForItem(at index: Int) -> UICollectionViewCell {
+    override func cellForItem(at index: Int) -> UICollectionViewCell {
         let cell = collectionContext!.dequeueReusableCell(of: DemoCell.self, for: self, at: index) as! DemoCell
         cell.label.text = object?.name
         return cell
     }
     
-    func didUpdate(to object: Any) {
+    override func didUpdate(to object: Any) {
         self.object = object as? DemoItem
     }
     
-    func didSelectItem(at index: Int) {
+    override func didSelectItem(at index: Int) {
         if let identifier = object?.controllerIdentifier {
             let storyboard = UIStoryboard(name: "Demo", bundle: nil)
             let controller = storyboard.instantiateViewController(withIdentifier: identifier)

Examples/Examples-tvOS/IGListKitExamples/SectionControllers/HorizontalSectionController.swift

@@ -15,7 +15,7 @@
 import UIKit
 import IGListKit
 
-final class HorizontalSectionController: IGListSectionController, IGListSectionType, IGListAdapterDataSource {
+final class HorizontalSectionController: IGListSectionController, IGListAdapterDataSource {
     
     var number: Int?
     
@@ -32,25 +32,25 @@ final class HorizontalSectionController: IGListSectionController, IGListSectionT
         self.inset = UIEdgeInsets(top: 20, left: 0, bottom: 20, right: 0)
     }
     
-    func numberOfItems() -> Int {
+    override func numberOfItems() -> Int {
         return 1
     }
     
-    func sizeForItem(at index: Int) -> CGSize {
+    override func sizeForItem(at index: Int) -> CGSize {
         return CGSize(width: collectionContext!.containerSize.width, height: 340)
     }
     
-    func cellForItem(at index: Int) -> UICollectionViewCell {
+    override func cellForItem(at index: Int) -> UICollectionViewCell {
         let cell = collectionContext!.dequeueReusableCell(of: EmbeddedCollectionViewCell.self, for: self, at: index) as! EmbeddedCollectionViewCell
         adapter.collectionView = cell.collectionView
         return cell
     }
     
-    func didUpdate(to object: Any) {
+    override func didUpdate(to object: Any) {
         number = object as? Int
     }
     
-    func didSelectItem(at index: Int) {}
+    override func didSelectItem(at index: Int) {}
     
     // MARK: IGListAdapterDataSource
     

Examples/Examples-tvOS/IGListKitExamples/SectionControllers/LabelSectionController.swift

@@ -15,28 +15,28 @@
 import UIKit
 import IGListKit
 
-final class LabelSectionController: IGListSectionController, IGListSectionType {
+final class LabelSectionController: IGListSectionController {
     
     var object: String?
     
-    func numberOfItems() -> Int {
+    override func numberOfItems() -> Int {
         return 1
     }
     
-    func sizeForItem(at index: Int) -> CGSize {
+    override func sizeForItem(at index: Int) -> CGSize {
         return CGSize(width: collectionContext!.containerSize.width, height: 55)
     }
     
-    func cellForItem(at index: Int) -> UICollectionViewCell {
+    override func cellForItem(at index: Int) -> UICollectionViewCell {
         let cell = collectionContext!.dequeueReusableCell(of: LabelCell.self, for: self, at: index) as! LabelCell
         cell.label.text = object
         return cell
     }
     
-    func didUpdate(to object: Any) {
+    override func didUpdate(to object: Any) {
         self.object = String(describing: object)
     }
     
-    func didSelectItem(at index: Int) {}
+    override func didSelectItem(at index: Int) {}
     
 }

Guides/Best Practices and FAQ.md

@@ -4,7 +4,7 @@ This guide provides notes and details on best practices in using `IGListKit`, ge
 
 ## Best Practices
 
-- We recommend adding an assert to check [`-isKindOfClass:`](https://developer.apple.com/reference/objectivec/1418956-nsobject/1418511-iskindofclass) on the object you receive in [`-didUpdateToObject:`](https://instagram.github.io/IGListKit/Protocols/IGListSectionType.html#/c:objc(pl)IGListSectionType(im)didUpdateToObject:) in your section controllers. 
+- We recommend adding an assert to check [`-isKindOfClass:`](https://developer.apple.com/reference/objectivec/1418956-nsobject/1418511-iskindofclass) on the object you receive in [`-didUpdateToObject:`](https://github.com/Instagram/IGListKit/blob/master/Source/IGListSectionController.h#L63-L72) in your section controllers. 
 This makes it easy to track down easily-overlooked mistakes in your [`IGListAdapaterDataSource`](https://instagram.github.io/IGListKit/Protocols/IGListAdapterDataSource.html#/c:objc(pl)IGListAdapterDataSource(im)listAdapter:sectionControllerForObject:) implementation. 
 If this assert is ever hit, that means `IGListKit` has sent your section controller the incorrect type of object. 
 This would only happen if your objects provide *non-unique* diff identifiers. 

Guides/Getting Started.md

@@ -8,23 +8,29 @@ After installing `IGListKit`, creating a new list is easy.
 
 ### Creating a section controller
 
-Creating a new section controller is simple. You subclass `IGListSectionController` and conform to the `IGListSectionType` protocol. Once you conform to `IGListSectionType`, the compiler will make sure you implement all of the required methods.
+Creating a new section controller is simple. Subclass `IGListSectionController` and override at least `cellForItemAtIndex:` and `sizeForItemAtIndex:`.
 
 Take a look at [LabelSectionController](https://raw.githubusercontent.com/Instagram/IGListKit/master/Examples/Examples-iOS/IGListKitExamples/SectionControllers/LabelSectionController.swift) for an example section controller that handles a `String` and configures a single cell with a `UILabel`.
 
 ```swift
-class LabelSectionController: IGListSectionController, IGListSectionType {
-  // ...
+class LabelSectionController: IGListSectionController {
+  override func sizeForItem(at index: Int) -> CGSize {
+    return CGSize(width: collectionContext!.containerSize.width, height: 55)
+  }
+
+  override func cellForItem(at index: Int) -> UICollectionViewCell {
+    return collectionContext!.dequeueReusableCell(of: MyCell.self, for: self, at: index)
+  }
 }
 ```
 
 ### Creating the UI
 
-After creating at least one section controller, you must create an `IGListCollectionView` and `IGListAdapter`.
+After creating at least one section controller, you must create a `UICollectionView` and `IGListAdapter`.
 
 ```swift
 let layout = UICollectionViewFlowLayout()
-let collectionView = IGListCollectionView(frame: .zero, collectionViewLayout: layout)
+let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
 
 let updater = IGListAdapterUpdater()
 let adapter = IGListAdapter(updater: updater, viewController: self, workingRangeSize: 0)