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/RDEPUBReaderToolView.swift

@@ -0,0 +1,35 @@
+import UIKit
+
+open class RDEPUBReaderToolView: UIView {
+
+    private let lineView = UIView()
+
+    private let lineHeight: CGFloat = 0.5
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        translatesAutoresizingMaskIntoConstraints = false
+        addSubview(lineView)
+    }
+
+    public required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    open override func layoutSubviews() {
+        super.layoutSubviews()
+        lineView.frame = lineFrame(in: bounds)
+    }
+
+    open func apply(theme: RDEPUBReaderTheme) {
+        backgroundColor = .white
+        lineView.backgroundColor = UIColor.lightGray.withAlphaComponent(0.5)
+    }
+
+    open func lineFrame(in bounds: CGRect) -> CGRect {
+        CGRect(x: 0, y: 0, width: bounds.width, height: lineHeight)
+    }
+}
+
+final class RDEPUBReaderTintButton: UIButton {
+}