Some updates to the ancient music section

Spelling correction.  Remove the description of non-ancient rests since it is no longer exhaustive and duplicates other parts of the NR.  Grammar. Remove out-commented example. Edit ligature example to get rid of ledger lines, which are not appropriate with mensural music.

[PhilEHolmes, 2015-05-19 10:17:00]

Please review.

[mail_philholmes.net, 2015-05-19 13:01:41]

----- Original Message ----- 
From: ""Jürgen Reuter"" <reuter_j@web.de>
To: ""Jürgen Reuter"" <reuter_j@web.de>; <PhilEHolmes@googlemail.com>; 
<tdanielsmusic@googlemail.com>; <lilypond-devel@gnu.org>; 
<reply@codereview-hr.appspotmail.com>
Sent: Tuesday, May 19, 2015 11:52 AM
Subject: Re: Some updates to the ancient music section (issue 240810043 
byPhilEHolmes@googlemail.com)


>   Hi all,
>
>   On Tue, May 19, 2015 at 12:16 PM,  <PhilEHolmes@googlemail.com> wrote:
>   > Reviewers: Trevor Daniels,
>   >
>   > Message:
>   > Please review.
>   > ...
>   > Without replacing @code{Ligature_bracket_engraver} with
>   > -@code{Mensural_ligature_engraver}, the same music transcribes
>   > -to the following
>   > +@code{Mensural_ligature_engraver}, the same music looks as follows:
>
>
>   Just a small nitpick: The central point of replacing
>   Mensural_ligature_engraver with Ligature_bracket_engraver is a feature
>   that in musicology is called "transcription" from ancient to modern
>   music.  IMHO it's ok to remove the verb "transcribes" from this
>   specific sentence.  However, the main thing in this section is that
>   Lily supports automatic transcription of mensural ligatures.  Hence, I
>   would propose to keep the word "transcribe" or "transcription"
>   somewhere in that section.  Please also note that Sect. "2.9.6 Working
>   with ancient music--scenarios and solutions" contains a subsection on
>   transcribing Gregorian chant.  One could imagine to join -- or at least
>   cross-reference -- these two sections.
>
>   Best wishes,
>   Juergen

I've just updated http://lsr.di.unimi.it/LSR/Item?u=1&id=1001 to include 
that information.  I think this could then be included in place of the TBC 
in "Ancient and modern from one source", and this would then put some 
information into that section, and reference the word "transcription" in an 
appropriate place?

--
Phil Holmes

[Trevor Daniels, 2015-05-19 20:17:10]

LGTM

Trevor