#1204 Documentation and regtests needed for external font files

[Anonymous]

https://codereview.appspot.com/557640051
new: https://codereview.appspot.com/573730044

Originally created by: *anonymous

Originally created by: v.villenave

LilyPond is getting increasingly good at handling external fonts:
- ly:font-config-add-directory and ly:font-config-add-font have introduced the ability to use specific font files when compiling a score.
- OTF, TTF, Type1 and more recently WOFF fonts are supported (TeX fonts aren't, IIUC).
- Experimental support for 3rd-party music fonts (namely Gonville) has been introduced as well.

All of these nice features are currently not documented in the NR, nor are they demonstrated in the regtests. Can we/should we do something about it?

[Valentin Villenave]

facepalm. I got mixed up in my temporary git branches again.
Pushed as
https://git.savannah.gnu.org/cgit/lilypond.git/commit/?id=610f9d924a9d3403facbdb7aa344ab0277f70274

[David Kastrup]

"Valentin Villenave" v_villenave@users.sourceforge.net writes:

facepalm. I got mixed up in my temporary git branches again.
Pushed as
https://git.savannah.gnu.org/cgit/lilypond.git/commit/?id=610f9d924a9d3403facbdb7aa344ab0277f70274

This time my Patchy considered itself in agreement.

--
David Kastrup

[Valentin Villenave]

n-th time’s the charm: pushed as https://git.savannah.gnu.org/cgit/lilypond.git/commit/?id=8b1785909543f6ecb97a962067e75bb97e2caec1