code: public PropertiesWriter append( final String comment )
      {
          String commentToAdd = "#" + comment;
          if( comment == null )
          {
              commentToAdd = "#";
          }
          m_content.add( commentToAdd );
          return this;
      }
docs: Appends a comment to be written.
  
  @param comment The comment to add to the Properties file.
  
  @return self for a fluent api