[setHeightTracksTextView:] make sure that the view post changes
and that notifications are only send once.
git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/gui/trunk@8038 72102866-910b-0410-8b05-ffd578937521
Check text view in [_textViewFrameChanged:].
Don't add observer if text view is nil in
[setHeightTracksTextView:] and [setWidthTracksTextView:]
git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/gui/trunk@7678 72102866-910b-0410-8b05-ffd578937521