title: Sublime Text 2 RegEx replace n with n+1
body: <p>Using RegEx search and replace with Sublime Text 2, how can I replace my pattern matches (n) with n+1? And if there is no way to do this with search and replace, is there another easy way to do it?</p>
  
  <p>My RegEx pattern is <code>^(\d{1,4})\n</code>, and I'd like to be able to do <code>$1+1</code>, which currently just outputs the match with a literal "+1".</p>