mei-CMN disallows accidental apparatus

[rettinghaus]

<accid> is not allowed within <lem> and <rdg>, although <app> is allowed within <note>. It does work, if mei-all is being used.

Seems to be connected to #566

[MirijamBeier]

The same applies to <artic> within <rdg>, as we've just noticed working on MEI 4-files at the Digital Interactive Mozart Edition. Are there any plans to allow <accid> and <artic> within <lem> and <rdg> in mei-CMN? We would appreciate that.

[rettinghaus]

@kepper @ahankinson Any idea how to fix this? I have none.

[kepper]

We would have to see if model.noteModifierLike can serve as a good starting point (I haven't thought through yet if the <dot> in there may have side effects), and then make this a member of model.rdgPart.music. Without too much thinking about directions of memberships, this should come to the right end – at least it's worth a try…