Enhancement to comments_popup_link()

[zeo]

Currently "Comments Off" is wrap with <span> tag, but not "Enter your password to view comments." if post requires password.

The idea is to wrap "Enter your password to view comments." with span tag, have its own css class e.g enter-password. Also adds $css_class if set. This way, theme author can easily style it based on post / comment status condition.

And add another paramater $password so that theme author can customize the text to display if post is password protected.

Need 2nd opinion with the attached patch.