Move menu validations to the app delegate.

Mac/AppDelegate.swift

@@ -282,7 +282,7 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSUserInterfaceValidations,
 			return mainWindowController?.isOpen ?? false
 		}
 		if item.action == #selector(showAddFeedWindow(_:)) || item.action == #selector(showAddFolderWindow(_:)) {
-			return !isDisplayingSheet
+			return !isDisplayingSheet && !AccountManager.shared.activeAccounts.isEmpty
 		}
 		return true
 	}

Mac/MainWindow/MainWindowController.swift

@@ -228,14 +228,6 @@ class MainWindowController : NSWindowController, NSUserInterfaceValidations {
 			return true
 		}
 		
-		if item.action == #selector(showAddFeedWindow(_:)) {
-			return canAddNewFeed()
-		}
-		
-		if item.action == #selector(showAddFolderWindow(_:)) {
-			return canAddNewFolder()
-		}
-
 		return true
 	}
 
@@ -600,14 +592,6 @@ private extension MainWindowController {
 		return currentTimelineViewController?.canMarkAllAsRead() ?? false
 	}
 	
-	func canAddNewFeed() -> Bool {
-		return sidebarViewController?.canAddNewFeed() ?? false
-	}
-	
-	func canAddNewFolder() -> Bool {
-		return sidebarViewController?.canAddNewFolder() ?? false
-	}
-
 	func validateToggleRead(_ item: NSValidatedUserInterfaceItem) -> Bool {
 
 		let validationStatus = currentTimelineViewController?.markReadCommandStatus() ?? .canDoNothing

Mac/MainWindow/Sidebar/SidebarViewController.swift

@@ -361,14 +361,6 @@ protocol SidebarDelegate: class {
 		
 	}
 	
-	func canAddNewFeed() -> Bool {
-		return !accountNodes.isEmpty
-	}
-	
-	func canAddNewFolder() -> Bool {
-		return !accountNodes.isEmpty
-	}
-	
 }
 
 // MARK: - NSUserInterfaceValidations