conventions for private/public/protected

[riffraff]

I realized these are missing, both as editor conventions (e.g., if base indent is 2, indent "private" keyword by 1 is what I use) and coding style. Off the top of my head

• should we use _foo for private methods ? I always thought it makes sense (way more then private does in ruby), but I seldom see it used

• should we use private/protected methods at all?

• when should we use private with or without arguments?

  private def foo()... end;

  def foo.... end private :foo