Fixes for USE_TZ and Diango 1.4's ModelAdmin.change_view argument changes

* The latest changes where use_utc was used in place of datetime.now assumes that USE_TZ=True.  This fixes it so the pages will save when USE_TZ=False.  

* I noticed the Revisions lists next to placeholders were missing since upgrading to Django 1.4.  The ModelAdmin.change_view arguments changed in Django 1.4 and that's fixed by this commit as well.