title: Transliterate/transpose the characters in the NSString
body: <p>I want to transliterate a cyrillic string to it's closest latin equivalent. E.g. "матрешка" => "matreshka", "водка" => "vodka". So ideally I want some ready to use method on the NSString or somewhere else that already knows everything about the alphabets and can do the conversation.</p>
  
  <p>But if such functionality doesn't exist in the iOS APIs then I will be totally happy with something like ruby's <strong>tr</strong> method that just replaces the characters in a string using a simple mapping specified as a parameter.</p>
  
  <pre><code>"баба".tr('абвгд', 'abvgd')
  </code></pre>