Remove unneeded singleton since SBApplication is supposed to own it

Author: NattyNarwhal

Submariner/SBAppDelegate.swift

@@ -14,15 +14,6 @@ fileprivate let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, catego
 @main
 @objc(SBAppDelegate) class SBAppDelegate: NSObject, NSApplicationDelegate, NSMenuDelegate, NSUserInterfaceValidations {
 
-    // #MARK: - Singleton
-    
-    private static var _sharedInstance = SBAppDelegate()
-    
-    // FIXME: Make var
-    @objc static func sharedInstance() -> SBAppDelegate {
-        return _sharedInstance
-    }
-    
     // #MARK: - Initialization
 
     let databaseController: SBDatabaseController

Submariner/SBPlayer.swift

@@ -411,8 +411,10 @@ extension NSNotification.Name {
             // Default, so not one of the buttons (if we have them or not)
             if response.actionIdentifier == UNNotificationDefaultActionIdentifier {
                 DispatchQueue.main.async {
-                    SBAppDelegate.sharedInstance().zoomDatabaseWindow(self)
-                    SBAppDelegate.sharedInstance().goToCurrentTrack(self)
+                    if let appDelegate = NSApp.delegate as? SBAppDelegate {
+                        appDelegate.zoomDatabaseWindow(self)
+                        appDelegate.goToCurrentTrack(self)
+                    }
                 }
             } else if response.actionIdentifier == "SubmarinerSkipAction" {
                 self.next()