Re: doc additions

[Werner]

> 
btw

I don't find an explicit explanation about the possibility to define clefs like
\clef F (= \clef bass)
\clef "G" (= \clef "treble")
(about the "" there is said something in context with _8 ^15 etc.)

This could be added in NR 1.1.3 and in LM (Chapter 2, Clef).

and btw

The file-names could include the version-number, which one finds at the first
page in the last line [e.g. lilypond-2.12.2.pdf or Lilypond-NR-2.12.2 or
Lilypond-2.12.2-NR.pdf]. For that it would be necessary to redefine all links.
 
As the NR is called just lilypond.pdf, it could include lilypond-learning.pdf -
otherwise it's not clear, why it's not called Lilypond-NR.pdf and 
Lilypond-LM.pdf.