Popover was missing code to apply quite a number of :parts overrides,…

… for both :style and :attr

Merge pull request #346 from day8/missing-release

Adjust flex style, layering, borders

Remove println

Adjust flex-child style & internal layering

Remove println

Update changelog

[cleanup]

[nested-grid] Fix cell-wrapper styling

Fix alt-key debugging

[nested-grid] Tweak row-header borders