message: Guard against nil window
diff: @@ -114,6 +114,7 @@ class SafariExtensionViewController: SFSafariExtensionViewController, WKScriptMe
  let options = TabQueryOptions()
  options.active = true
  SFSafariApplication.getActiveWindow { win in
  + if ((win) != nil) {
  processWindowsForTabs(wins: [win!], options: options, complete: { tabs in
  let response = AppMessage()
  response.command = "app_message"
  @@ -126,6 +127,7 @@ class SafariExtensionViewController: SFSafariExtensionViewController, WKScriptMe
  })
  }
  }
  + }
  func sendContextMenuData(contextInfo: ContextMenuData) {
  NSLog("Getting current page")
  