Small changes to the conversion of YAML to text.
- The textarea is 150 columns but YAMLBeans has a default of 130. Set it explicitely.
  TODO: make this a user configuration item.
- One user objected to the sequence YAMLBeans read file, convert to text "eating" all blank lines in the .yml.
  Fixed by using a internal Writer to add a blank line to top level list items.