* Reformat GTK *.ui files
Remove useless comments since we're mostly editing those files by hand
now. Wrap multi-line text values in CDATA to avoid automated formatters
changing whitespace there in any way. Collapse empty elements.
* Switch from plain `GtkLabel`s to `GtkFrame`s for sections
Frames are reported as groupings by assistive technologies.
* Fix minor usability issues
* Make value labels labelled and selectable
f6e1bb2d70