Fix tab titles

Make them more informative during load, especially when tabs are loading
in background: display the host name.

Vienna/Sources/Main window/BrowserTab+Interface.swift

@@ -140,13 +140,13 @@ extension BrowserTab {
     }
 
     func updateTabTitle() {
-        if self.url != webView.url || self.url == nil {
+        if self.url != webView.url || webView.url == nil {
             // Currently loading (the first time), webview title not yet correct / available
             self.title = self.url?.host ?? NSLocalizedString("New Tab", comment: "")
         } else if let title = self.webView.title, !title.isEmpty {
             self.title = title
-        } else {
-            // Webview is about:blank or empty
+        } else if (self.title ?? "").isEmpty {
+            // we haven't yet set a title and Webview is about:blank or empty
             self.title = NSLocalizedString("New Tab", comment: "")
         }
     }