New manual chapter: Putting it all together

[Graham Percival]

I'm proposing that we add a chapter (to become the new chapter 4) which
demonstrates practical examples of lilypond.  For example,

\header{
  title = \markup \center-align < "Title first line" "Title second 
line, longer" >
  subsubtitle = #(string-append "subsubtitle LilyPond version " 
(lilypond-version))
  composer =  \markup \center-align < "composer" \small "(1847-1973)" >
}

All this information is present in the manual somewhere, but beginners 
may
have difficulty putting it together.  This kind of doc has been 
requested
numerous times, and most people who start to write their own lilypond
tutorial want to do this kind of thing.  The idea is to have three or 
four
complicated but short examples (maybe 20 lines each), with wordy
explanations for each line.  Basically, it's an Advanced Tutorial.


Any objections?
- Graham