[tei-council] time & date model classes: lump 'em?

[Syd Bauman]

Since we've removed <(date|time)(Range|Struct)>, we have some leaner
classes.

- The class model.dateLike has one member, <date>.
- The class model.timeLike has one member, <time>.
- Everywhere one of these model classes is used, so is the other,
  with the one exception of model.recordingPart, which contains only
  model.dateLike, and which itself is only used as the content of
  <recording>.

So the question is whether to leave things as they are, with 2 model
classes with 1 member each, or combine them into 1 model class with 2
members.

Combining them makes the TEI class system 1 quantum less complicated,
with only the smallest disadvantage in vanilla schemas (<recording>
gets <time> as a child ... some might even say it's a good idea).
However, leaving 2 classes gives users more flexibility with their
customizations.

Thoughts?