title: add checkboxes in twitter bootstrap dropdown
body: <p>i am using twitter bootstrap for my project.</p>
  
  <p>I want to add checkboxes in dropdown, something similar to <a href="http://jsfiddle.net/qG7c4/" rel="noreferrer">http://jsfiddle.net/qG7c4/</a></p>
  
  <p>File: bootstrap-dropdown.js</p>
  
  <p>Example: <a href="http://twitter.github.com/bootstrap/javascript.html#dropdowns" rel="noreferrer">http://twitter.github.com/bootstrap/javascript.html#dropdowns</a></p>
  
  <p>problem is, that dropdown get closed on click of every checkbox, i don't want this to be closed on click of checkbox, so that user can select multiple checkboxes easily.</p>
  
  <p>What changes i need to do in javascript for this?</p>