Some minor tweaks to the admin changelist styles for the new action menus. Cut...

Some minor tweaks to the admin changelist styles for the new action menus. Cut out extranous margins around checkboxes on changelists and styled the action row to stack better with the date hierarchy browser.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10181 bcc190cf-cafb-0310-a4f2-bffc1f526a37