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/EPUBUI/ReaderController/RDEPUBSelectionState.swift

@@ -0,0 +1,31 @@
+
+import Foundation
+
+enum RDEPUBSelectionState: Equatable {
+
+    case idle
+
+    case selecting(anchor: Int)
+
+    case selected(RDEPUBSelection)
+
+    case committingAction(RDEPUBSelection, action: RDEPUBAnnotationMenuAction)
+
+    var hasSelection: Bool {
+        switch self {
+        case .idle:
+            return false
+        case .selecting, .selected, .committingAction:
+            return true
+        }
+    }
+
+    var selection: RDEPUBSelection? {
+        switch self {
+        case .idle, .selecting:
+            return nil
+        case .selected(let selection), .committingAction(let selection, _):
+            return selection
+        }
+    }
+}