Re: Adds a glyph for tied lyrics. (issue4808074)

[bordage . bertrand]

I forgot these cases (o~è~in; a~è~in; o~è~an...).  They are often elided
("quest'in" instead of "questa~è~in") by editors and composers.

> So your view is that lyric ties are not used in the real world?  I
> still feel them as a pedagogy resource for young musicians or
> something.  Or maybe old scores did not use them and they are now more
> often used. I don't know.

Several famous editors use them, with no particular rule.
Let's take the example of Ricordi Milano.

In this score, published around 1982, there's no ties (we can see a "na
è in" in the beginning):
http://petrucci.mus.auth.gr/imglnks/usimg/2/20/IMSLP81325-PMLP165637-la_danza.pdf

In this one, published around 1925, we can find ties (and it's not a
beginner score!):
http://216.129.110.22/files/imglnks/usimg/2/29/IMSLP80146-PMLP162554-Vivaldi_-_Agitata_da_due_venti__Griselda_.pdf

In every recent score I have from them, they always use ties. Those
which were done using traditional engraving as those using Finale.

I will have to do a better patch...

http://codereview.appspot.com/4808074/