Comment unpublish feature to node owner

Unpublish - set comment to Not published status

* Purpose of this patch:
Node owner can Delete or Unpublish unwanted comments.

* Why this patch is needed ?
Voting system does not fit always to everysolution and there also never be so much admins to manage all comments in blog system if there will be to many users. This will be more natrual if node owner can manage he's own nodes from top to bottom.

* How it works:

Configuration block "Comment management settings" is in: http://example.com/admin/comment/configure
Ther is two things.
1. Patch adds possibility to change Delete button to Unpublish (by default it is Delete as it were before).
2. Patch adds possibility to enable Delete/Unpublish button to Node owner (by default it is Disabled)

* Other things what i discovered when i developed (not tied with this patch)
1. If User has FLAT LIST display then you still can answer to comments, but you dont see them as answered. so, if user unpublishes/deletes bad comment where is answers then maybe all comments can be gone.
2. If You delete Node then node does not check - do you or do you not have comments. So, comments will remain to database. I think they should not be.