Doc addition

[Markus Schneider]

Hello all,

in "9.1.2 Setting automatic beam behavior" I'd like to propose a doc
addition regarding automatic beam behaviour for 'unusual' time signatures.
(http://lilypond.org/doc/v2.9/Documentation/user/lilypond/Setting-automatic-
beam-behavior.html#Setting-automatic-beam-behavior)

Below "In 4/4 time signature, this means that automatic beams could end only
on 3/8 and on the fourth beat of the measure (after 3/4, that is 2 times
3/8, has passed within the measure)." please add:

---
"If any unexpected beam behaviour occurs, check the default auto beam
settings in scm/auto-beam.scm for possible interference, because the beam
endings defined there will still apply on top of your own overrides. Any
unwanted endings have to be reverted first for your time signature(s)."

Example: (3 4 3 2)-beam endings in 12/8

#(revert-auto-beam-setting '(end * * 12 8) 3 8)
#(revert-auto-beam-setting '(end * * 12 8) 3 4)
#(revert-auto-beam-setting '(end * * 12 8) 9 8)
^^^ these are the reverts derived from scm/auto-beam.scm regarding 12/8.

Then, you can use
#(override-auto-beam-setting '(end 1 8 12 8) 3 8)
#(override-auto-beam-setting '(end 1 8 12 8) 7 8)
#(override-auto-beam-setting '(end 1 8 12 8) 10 8)

---

This proposal is a summary of this thread:
http://lists.gnu.org/archive/html/lilypond-user/2006-08/msg00052.html

HTH
Markus