Fix Command-W behavior according to tab count

* Change tab count to behave similarly whether using old or new browser
* Fix occurence of shortcut adaptations:
  - Command-W closes the window if tab count is 0 or 1.
  - If tab count is greater, Command-W closes tab, Command-Option-W
    closes all tabs except the primary one and Command-Shift-W closes
    the window
* Send missing notification.

Cherry-pick of commit 4ffdd65
Issue #1664

Author: barijaona

Vienna/Sources/Application/AppController.m

@@ -1639,7 +1639,7 @@ -(void)selectFolder:(NSInteger)folderId
  */
 -(void)updateCloseCommands
 {
-	if (self.browser.browserTabCount == 0 || !self.mainWindow.keyWindow)
+	if (self.browser.browserTabCount <= 1 || !self.mainWindow.keyWindow)
 	{
 		closeTabItem.keyEquivalent = @"";
 		closeAllTabsItem.keyEquivalent = @"";
@@ -3634,7 +3634,7 @@ -(BOOL)validateMenuItem:(NSMenuItem *)menuItem
 	}
 	else if (theAction == @selector(previousTab:))
 	{
-		return isMainWindowVisible && self.browser.browserTabCount > 0;
+		return isMainWindowVisible && self.browser.browserTabCount > 1;
 	}
 	else if (theAction == @selector(nextTab:))
 	{

Vienna/Sources/Main window/TabbedBrowserViewController.swift

@@ -312,6 +312,10 @@ extension TabbedBrowserViewController: MMTabBarViewDelegate {
     func tabView(_ tabView: NSTabView, didSelect tabViewItem: NSTabViewItem?) {
         NotificationCenter.default.post(name: NSNotification.Name(rawValue: "MA_Notify_TabChanged"), object: tabViewItem?.view)
     }
+
+    func tabViewDidChangeNumberOfTabViewItems(_ tabView: NSTabView) {
+        NotificationCenter.default.post(name: NSNotification.Name(rawValue: "MA_Notify_TabCountChanged"), object: tabView)
+    }
 }
 
 // MARK: WKUIDelegate + BrowserContextMenuDelegate

Vienna/Sources/Main window/WebViewBrowser.m

@@ -210,11 +210,7 @@ -(void)closeTab:(NSTabViewItem *)tabViewItem
  */
 -(NSInteger)browserTabCount
 {
-    if (self.primaryTab) {
-        return self.tabBarControl.numberOfTabViewItems - 1;
-    } else {
-        return self.tabBarControl.numberOfTabViewItems;
-    }
+    return self.tabBarControl.numberOfTabViewItems;
 }
 
 /* showPreviousTab