refactor: rename RDReaderView -> RDEpubReaderView, update pod config and docs

- Rename source module from RDReaderView to RDEpubReaderView
- Move all source files from Sources/RDReaderView/ to Sources/RDEpubReaderView/
- Update podspec: RDReaderView.podspec -> RDEpubReaderView.podspec
- Update Podfile, demo project, and CocoaPods config for new pod name
- Delete old RDReaderView pod support files from ReadViewDemo/Pods
- Add new RDEpubReaderView pod support files
- Update documentation (API ref, architecture, UML, conventions, etc.)
- Add FixedLayoutRotationTests
- Update .gitignore: exclude .DS_Store, manual unpack backups, _ssoft-output

Sources/RDEpubReaderView/ReaderView/RDEpubReaderPageChildViewController.swift

@@ -0,0 +1,50 @@
+
+import UIKit
+
+class RDEpubReaderPageChildViewController: UIViewController {
+
+    private let contentContainerView = UIView()
+
+    var contentView: UIView? {
+        didSet {
+            guard isViewLoaded else { return }
+            installContentView()
+        }
+    }
+
+    var pageNum: Int = 0
+
+    init(contentView: UIView?, pageNum: Int = 0) {
+        self.contentView = contentView
+        self.pageNum = pageNum
+        super.init(nibName: nil, bundle: nil)
+    }
+
+    override func loadView() {
+        view = UIView()
+        view.backgroundColor = .clear
+        contentContainerView.frame = view.bounds
+        contentContainerView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+        contentContainerView.backgroundColor = .clear
+        view.addSubview(contentContainerView)
+        installContentView()
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+    }
+
+    private func installContentView() {
+        contentContainerView.subviews.forEach { $0.removeFromSuperview() }
+        guard let contentView else { return }
+        contentView.removeFromSuperview()
+        contentView.frame = contentContainerView.bounds
+        contentView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+        contentContainerView.addSubview(contentView)
+    }
+
+}