Use split view for Settings

pass/Controllers/SettingsSplitViewController.swift

@@ -0,0 +1,24 @@
+//
+//  SettingsSplitViewController.swift
+//  pass
+//
+//  Created by Mingshen Sun on 6/21/17.
+//  Copyright © 2017 Bob Sun. All rights reserved.
+//
+
+import UIKit
+
+class SettingsSplitViewController: UISplitViewController, UISplitViewControllerDelegate {
+    override func viewDidLoad() {
+        self.delegate = self
+        self.preferredDisplayMode = .allVisible
+    }
+    
+    func splitViewController(
+        _ splitViewController: UISplitViewController,
+        collapseSecondary secondaryViewController: UIViewController,
+        onto primaryViewController: UIViewController) -> Bool {
+        // Return true to prevent UIKit from applying its default behavior
+        return true
+    }
+}