centering the new Lyrics

[Keith OHara]

Dear engravers of lyrics,

The next version of LilyPond will handle empty spaces within lyrics differently.

If we have some adjacent lines of lyrics, version 2.12 collapses any empty 
sections, so the set of lines collapses to the minimum vertical height.

The new system by default preserves the space for the empty sections[*], so 
that the lines remain consistently spaced.   So far I have heard people want to 
do two things:
(1) let interrupted lyrics collapse to a single line,
(2) perfectly center a line of lyrics between two staves.
The new system is very flexible, so we can do these things (attached). But the 
new system is complicated, so I always forget and need to relearn how to use it.

I want to make a new snippet(s), or a shortcut command(s).  Do people really 
want to do such things? What else? Is the attached .ly self-explanatory?
--
Keith

note[*] except between one line of Lyrics attached to the next staff #UP and 
another line attached to the next staff #DOWN.  In this case LilyPond tries to 
let the lyrics collapse, but there is a bug (issue 1309) that sometimes 
prevents them from lining up perfectly.

CenterLyrics.ly
Description: Binary data

defaultNnewLyrics.png
Description: PNG image

adjustedLyrics.png
Description: PNG image