Account for distribution item insets when applying orthogonal alignment in distribution

[NickEntin]

We currently ignore distribution item insets when performing orthogonal alignment. This would be useful for use cases such as aligning baselines in horizontal alignment. It also opens the possibility of uneven orthogonal alignment in distributions by creating distribution items with custom insets.

[NickEntin]

I'm gonna call this a bug. It's not actually documented behavior either way, but I think the current behavior is the less intuitive - we're giving consumers a way to provide orthogonal insets, then completely ignoring those values.