Rel 3.0.0

[danirus]

Release 3.0.0:

• Implements enhancement reported in #161.
• Fixes issue #194, about setting COMMENTS_HIDE_REMOVED and the new setting COMMENTS_XTD_PUBLISH_OR_WITHHOLD_NESTED. Up until v3.0.0 removed comments were listed but their content were not displayed. They showed a "comment has been removed" message instead. That behaviour didn't fully comply with parent's app, django-comments setting COMMENTS_HIDE_REMOVED. By default COMMENTS_HIDE_REMOVED is True, which has the effect of hiding removed comments. As of v3.0.0 this is also the behaviour of django-comments-xtd. Additionally a new setting COMMENTS_XTD_PUBLISH_OR_WITHHOLD_NESTED has been created to control whether nested comments of a comment being removed or approved will be withhold or published.
• Implements feature reported in #210.