Reorganize MathEditorSwift and MathKeyboardSwiftUI into standard SPM layout

Package.swift

@@ -22,22 +22,19 @@ let package = Package(
   targets: [
     .target(
       name: "MathEditorSwift",
-      dependencies: ["iosMath"],
-      path: "MathEditorSwift/Sources/MathEditorSwift"
+      dependencies: ["iosMath"]
     ),
     .testTarget(
       name: "MathEditorSwiftTests",
       dependencies: [
         "MathEditorSwift"
-      ],
-      path: "MathEditorSwift/Tests/MathEditorSwiftTests"
+      ]
     ),
     .target(
       name: "MathKeyboardSwiftUI",
       dependencies: [
         "MathEditorSwift"
       ],
-      path: "MathKeyboardSwiftUI/Sources/MathKeyboardSwiftUI",
       resources: [.process("Resources")]
     ),
   ]

MathEditorSwift/Sources/MathEditorSwift/MTEditableMathLabelSwift.swift → Sources/MathEditorSwift/MTEditableMathLabelSwift.swift

@@ -69,7 +69,7 @@ public final class MTEditableMathLabelSwift: MTView, MTKeyInput {
   }
 
   @objc private var cancelImage: MTCancelView?
-  @objc private var caretView: MTCaretView!
+  @objc private(set) var caretView: MTCaretView!
   public weak var delegate: MTEditableMathLabelDelegate?
   public weak var keyboard: MTMathKeyboard?