title: Find matching brackets using regular expression
body: <p>Assuming I have this <code>string: "abc{def{ghi{jkl}mno{pqr}st}uvw}xyz"</code></p>
  
  <p>and I want to match this: <code>"{def{ghi{jkl}mno{pqr}st}uvw}"</code></p>
  
  <p>what should my regular expression look like..?</p>
  
  <p>In other words, the match should start with "{" and end with "}", but it must have as many {'s as }'s in between.</p>