[FIX] forums: Seems html mails "doubled" blank lines are in fact quadrupled, also, some mail programmes have the attachment at the root of the disposition: attachment part, not in parts within that. (plus a confirm message typo fix)

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/13.x@52811 b456876b-0849-0410-b77d-98878d47e9d5
[FIX] forums: Improve confirm text on what you are deleting

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/13.x@52814 b456876b-0849-0410-b77d-98878d47e9d5