Tie properties vs. slur properties.

[Carl Sorensen]

The tie interface has height-limit and ratio as part of Tie.details.

The slur interface has height-limit and ratio as part of Slur (not
embedded in Slur.details).

Is there a reason for this difference, or is it just due to never making
the two be consistent?  If there is no reason for the difference, I think
the two should be rationalized, probably by moving Slur.height-limit and
Slur.ratio to Slur.details.height-limit and Slur.details.ratio.

Before I make such a patch, could you tell me if it makes sense to do so?

Thanks,

Carl