Cavum glyphs

[henryso]

Implemented expanded set of cavum glyphs (#844).

Note: this is a seriously big and potentially breaking pull request and should not be pulled into 4.2.

Tests obviously change because of this.

Please review and merge if satisfactory.

[eroux]

Thanks, that's quite impressive! I'll review it tonight

[eroux]

I'm getting a warning in this branch, but it may come from another PR:

struct.c: In function ‘gregorio_change_shape’:
struct.c:380:20: warning: variable ‘old_shape’ set but not used [-Wunused-but-set-variable]
     gregorio_shape old_shape;

[eroux]

Well, apart from this tiny warning everything looks really perfect! Thank you very much for this, I think this is a great feature that will allow gregorian chant typography to go one step further. Ok for me to be merged (with or without the fix for the warning, it can be for another PR)

[henryso]

It's most likely from here. The cavum changes reduced a lot of "special" glyph transformation code. I will try to fix it tonight and add the tests you requested.

[henryso]

I made the changes and added the tests. Please review at your leisure.

[eroux]

Perfect, thanks a lot!