Bagpipe docs

[Noeck]

in this section of the manual (2.16 as well as 2.17):
http://lilypond.org/doc/v2.16/Documentation/notation/bagpipes
the first mentioned advantage of bagpipe.ly is that \taor is short for
\grace { \small G32[ d G e] }

But this line is no valid syntax without bagpipe.ly (due to the G).

The meaning of pitches with bagpipe.ly should be explained before, not
afterwards. (A more minimal correction would be to change this line to usual
lilypond syntax using , and ' .)

In addition, the commands of ly/bagpipe.ly should be explained, at least on
of each type. Right now, the user needs to read bagpipe.ly to know the commands.