Vertically aligning components in St

[Jason Heeris <jason heeris gmail com>]

I've been trying to vertically align components in an St.BoxLayout
(with vertical = false), but nothing I do seems to have any affect.
I've tried setting 'vertical-align' in the CSS for a component, and
setting y_align and y_expand on both the components and the BoxLayout.
The components always end up aligned along the top edge of the
BoxLayout.

How can I vertically centre components? Or better yet, can I align
text-based components (eg. labels and text fields) along the text
baseline?

— Jason