Duplicated comments still send the comment_was_posted signal

django_comments return the previews comment if it checked a duplicated comments. This would result in sending the comment_was_posted signal twice. These would get some unexpective results. For example, if I send a notification in comment_was_posted, then user will receive two notifications even there is only one comment. What do you think about this issue? If you think it is nesessary to fix it. I will make a pull requests.

In addition, do you have any plan convert the view to class based view? If we do this, people can overide a few methods then they can fix the above issue.

[claudep]

If you can provide a patch with an appropriate test, it will be welcome.

About class-based-views, this is #82. It seems however the poster was short of time...