Deal with final folder name issues due to Apple's case insensitive case preserving behavior.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

WireGuard/Coordinators/Coordinator.swift

@@ -0,0 +1,34 @@
+//
+//  Coordinator.swift
+//  WireGuard
+//
+//  Created by Jeroen Leenarts on 23-05-18.
+//  Copyright © 2018 WireGuard. All rights reserved.
+//
+
+import Foundation
+
+/// The Coordinator protocol
+public protocol Coordinator: class {
+
+    /// Starts the coordinator
+    func start()
+
+    /// The array containing any child Coordinators
+    var childCoordinators: [Coordinator] { get set }
+
+}
+
+public extension Coordinator {
+
+    /// Add a child coordinator to the parent
+    public func addChildCoordinator(_ childCoordinator: Coordinator) {
+        self.childCoordinators.append(childCoordinator)
+    }
+
+    /// Remove a child coordinator from the parent
+    public func removeChildCoordinator(_ childCoordinator: Coordinator) {
+        self.childCoordinators = self.childCoordinators.filter { $0 !== childCoordinator }
+    }
+
+}