Klaus Rettinghaus
Klaus Rettinghaus
This removes `@lyric.name`, `@text.name` and `@fontname` with the respective `data.FONTNAME` from the schema. closes #716
[Chapter 13](https://music-encoding.org/guidelines/dev/content/linkingdata.html#ptrrefModule) and [Chapter 10](https://music-encoding.org/guidelines/dev/content/analysisharm.html#analysisDescribingRelationships) of the Guidelines should contain some information and examples on `@corresp`.
This moves `rotation` from `rend` into a new class `att.rotating` to be used in other elements, starting with `hairpin`.
Currently the values `count` and `ratio` are available in `@num.format`. There should be a third option (perhaps `note`), to be able to encode things like this: 
`` is not allowed within `` and ``, although `` is allowed within ``. It does work, if `mei-all` is being used. Seems to be connected to #566
Currently it is not possible to encode a double bar line consisting of two thick lines which can be found in several older prints.  Example from: _Leroy, Eugène: Méthode...
How to encode split stem notation?  For "easy" cases like altered unions in chords you can avoid split stem notation. [Dorico](https://steinberg.help/dorico/v2/en/dorico/topics/notation_reference/notation_reference_stems_altered_unisons_split_stems_c.html) lets you choose the display of these...
It would be nice if we could had a validation of the schema for every PR.
In `` we can use `form="pedstar"` or `form="line"` to encode the first and the last case of the following example.  To encode the middle one (which is quite common...
`` isn't allowed anywhere it would make sense (like `` or ``). Instead it is part of `model.textPhraseLike.limited`, which allows it in all those non-sense places like ``, ``, and...