New short and long lyric ties. (issue 4912041)

[bordage . bertrand]

Reviewers: ,

Message:
Hi everyone,

This follows 8d148ea05fa4b34f8cc3407e112363d715b27ad8

This is fully working, except for a small issue in make doc.
The two examples I put in the doc are working alone, but not with make
doc:
there should be short ties in "~è~", but we mysteriously get medium
ties.
This works if we change "è" for an ASCII character.
I think this is somehow due to an encoding issue in the "make doc"
process.

Cheers,
Bertrand

Description:
New short and long lyric ties.

Please review this at http://codereview.appspot.com/4912041/

Affected files:
  M Documentation/de/notation/vocal.itely
  M Documentation/es/notation/vocal.itely
  M Documentation/fr/notation/vocal.itely
  M Documentation/notation/vocal.itely
  M mf/feta-ties.mf
  M scm/define-markup-commands.scm