Changes

Summary

1. Move things related to Axis.label into the same paragraph (details)
2. Clarify that Axis.unit is required when specifying axis bounds (details)
3. Make Axis.unit default to "" (without yet specifying what the default means) (details)
4. First try at defining the meaning of empty Axis.unit (details)
5. Separate meanings of presence of axis bounds and presence of Axis.unit (details)
6. Ignore 'min' and 'max' when 'unit' is not recognized (details)

Move things related to Axis.label into the same paragraph

Clarify that Axis.unit is required when specifying axis bounds

Make Axis.unit default to "" (without yet specifying what the default means)

First try at defining the meaning of empty Axis.unit

Separate meanings of presence of axis bounds and presence of Axis.unit

Ignore 'min' and 'max' when 'unit' is not recognized