[FIX] newsletters: Although is_html doesn't get stored in the sent newsletters table it should respect the state of the "Is HTML" checkbox when sending.

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@48934 b456876b-0849-0410-b77d-98878d47e9d5
[FIX] Use correct URL in the help button

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@48935 b456876b-0849-0410-b77d-98878d47e9d5