branch created for Frescobaldi 3.1.x

[Wilbert Berendsen]

Dear co-developing friends,

I created a branch for Frescobaldi "3.1.x", intended for bug fixes and
backports. So a 3.1.3 release can be done when we deem it necessary.

Git master targets Frescobaldi 3.2.

One change in 3.2 is that qpageview has become a separate package, and
a dependency for Frescobaldi.

less relevant news: ;-) the parser (called parce) that will replace
ly.lex has developed nicely (lots of time these days!) See
https://parce.info .
More info at https://github.com/frescobaldi/python-ly/issues/139

Best wishes to everyone!

--
Wilbert Berendsen (www.wilbertberendsen.nl)