#5010 add choral and choral-cautionary accidental style

add choral and choral-cautionary accidental style This solves the issues mentioned in https://lists.gnu.org/archive/html/lilypond-user/2016-12/msg00201.html that accidental style could not apply to ChoirStaves in the same way as they did for PianoStaves, StaffGroups or GrandStaves. No impact on existing functionality, but now ChoirStaves are equal siblings w.r.t. accidental styles. In addition, a reasonable mix of the modern-voice and piano cautionary style is defined, which caters to both all-observant and egocentric readers.

https://codereview.appspot.com/311430043/

[Anonymous]

Passes make, make check and a full make doc.

[Anonymous]

This looks like it needs some work still - tweak the notation.tely description and add a changes.tely entry.

[Alexander Kobel]

update documentation for choral accidental style

http://codereview.appspot.com/311430043

[Anonymous]

Passes make, make check and a full make doc.

[Anonymous]

Patch on countdown for Dec 24th.

[Anonymous]

Patch counted down - please push.

[Thomas Morley]

pushed to staging as:

commit 8d8a54f9903e27263581f684b0a22dc2aca5d24c
Author: Alexander Kobel a-kobel@a-kobel.de
Date: Sun Dec 18 23:09:41 2016 +0100

update documentation for choral accidental styles

commit 3a0462a03c380657766e5e6903419dd49ce3dde2
Author: Alexander Kobel a-kobel@a-kobel.de
Date: Tue Dec 13 20:54:21 2016 +0100

add choral and choral-cautionary accidental style

commit f70f2a3261e4e58755821e2c7c82263b4824f8f4
Author: Alexander Kobel a-kobel@a-kobel.de
Date: Tue Dec 13 20:53:11 2016 +0100

add localAlterations property to ChoirStaff

[Graham Percival]

I have verified that these 3 commits are in git master.