Fixed #3758 -- Changed FormPreview template to use 'label' instead of 'verbose_name'. Also renamed 'Submit' button to 'Preview'. Thanks for the patch, erickt@dslextreme.com

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4757 bcc190cf-cafb-0310-a4f2-bffc1f526a37