title: how to get add a custom-parser in clj-time for AM / PM
body: <p>I am using clj-time for processing dates. I have a date <code>(def a (date-time 2011 01 01 11 30))</code>.</p>
  
  <p>I have defined a custom formatter <code>(def custom-formatter (formatter "hh:mm"))</code></p>
  
  <p>Now <code>(unparse custom-formatter a) =&gt; "11:30"</code>. </p>
  
  <p>However how do I build a formatter which gives me the AM and PM also respectively?</p>
  
  <p>Thanks,
  Murtaza</p>