title: default='False' is not reflected in django admin BooleanField when adding a new item
body: <p>1) When I add new item in django admin site, all checkboxes are set to true, even if default is set to false.</p>
  
  <p>2) If I don't touch any of them and save the item, when I reopen it to editing, all checkboxes are set to their apropriate values according the default (some true, some false).</p>
  
  <p>3) If I uncheck and recheck some which should be false by default, it doesn't have any effect after reopening (it's false, like i didn't touch it).</p>
  
  <p>4) If I uncheck some which should be true, it's value is saved (so it's false later)</p>
  
  <p>5) When I later edit the values they ARE saved exactly as expected. no glitches.</p>
  
  <p>Did you ever encounter similar glitches? Where was the problem?</p>
  
  <p>(on django 1.3.1, python 2.6.6, sqlite3)</p>
  
  <pre><code>Something1 = models.BooleanField(default='False')
  Something2 = models.BooleanField(default='True')
  Something3 = models.BooleanField(default='False')
  </code></pre>
  
  <p>thanks</p>