libscols: fix things not caught by a global rename

Signed-off-by: Ondrej Oprala <ooprala@redhat.com>
libsmartcols: add getters/setters

Signed-off-by: Ondrej Oprala <ooprala@redhat.com>
docs: refresh TODO

Signed-off-by: Karel Zak <kzak@redhat.com>
libsmartcols: add API for tree cloning

Signed-off-by: Ondrej Oprala <ooprala@redhat.com>