title: How to get coordinates (CGRect) for the selected text in UIWebView?
body: <p>I have simple UIWebView with loaded html.
  I want to show the PopoverView pointed to the selected text.
  I can get the menuFrame of the UIMenuController and use its rect, but the result isn't as accurate at the corners of the screen as I need.
  I can calculate the screen size and get menuFrame rect and then I can suppose where the selection may be found, but I want exactly know where is the selected text.
  Is it generally possible?</p>