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/ViewControllers/Identifyable.swift

@@ -0,0 +1,27 @@
+//
+//  Identifyable.swift
+//  WireGuard
+//
+//  Created by Jeroen Leenarts on 23-05-18.
+//  Copyright © 2018 WireGuard. All rights reserved.
+//
+
+import Foundation
+import UIKit
+
+public protocol Identifyable: class {
+    static var identifier: String { get }
+}
+
+public extension Identifyable {
+    static var identifier: String {
+        return String(describing: Self.self)
+    }
+}
+
+extension UIStoryboard {
+
+    public func instantiateViewController<T: Identifyable>(type: T.Type) -> T where T: UIViewController {
+        return self.instantiateViewController(withIdentifier: type.identifier) as! T // swiftlint:disable:this force_cast
+    }
+}