Speed of processing mensural music

[Phil Holmes]

I've been processing quite a bit of mensural music recently, and have 
noticed that it's slow compared to modern music.  That's OK: it's a niche 
application, so so be it.  I thought I'd see whether it used to be quicker. 
A simple benchmark (on Windows) gave the following:

2.12      5.0 sec
2.13.51  6.3s
2.13.52  14.7s
2.14.2 14.5s
2.19.6 13.7s

So we can see that something happened between 13.51 and 13.52 to slow 
processing down significantly.  I've done a bisect, and it appears it was 
the result of the commit that fixed

http://code.google.com/p/lilypond/issues/detail?id=1470

- which was one I wanted fixed....

If I use

\override PaperColumn.keep-inside-line = ##f
\override NonMusicalPaperColumn.keep-inside-line = ##f

and repeat the 2.19.6 test, I come down from 13.7 seconds to 9.4, which is 
pretty worth having.  Not sure why this has a disproportionate effect on 
mensural notation, but reckon it's worth a mention in the NR in the mensural 
music section?

--
Phil Holmes