Re: Issue 1350 in lilypond: make convert-ly restrict to `lilypond' enviroments

[lilypond]

Comment #1 on issue 1350 by lemzwerg: make convert-ly restrict to  
`lilypond' enviroments
http://code.google.com/p/lilypond/issues/detail?id=1350

Graham replied:

> What I consider problematic is that syntax changes aren't restricted to  
> lilypond
> environments.

This is useful for updating the docs -- we *want* it to change text
like "to change the direction of the slur, use \oldSlurUpCommand".

> To sum up: Keywords like `orientation' are far too frequent in normal
> text to be handled without protection if convert-ly is applied to
> lilypond-book (or texinfo) input.

I'm fine with this being a command-line option to convert-ly.
Actually, this could even be the default -- as long as there's a
(CG-documented) way to apply convert-ly to the entire document, I'm
happy with this change.