Honor trailing spaces in LabelString and friends

Honor trailing spaces in LabelString and friends

Remove the trimming operation on LabelString, LabelStringAppendix,
EndLabelString and LabelCounter. This trimming meant that quotes
strings were not preserved, which is wrong.

To preserve layouts, the Layout format has been updated to 64, so that
layout2layout can remove extra spaces on existing strings, which
ensures that behavior is unchanged for old layouts (courtesy of rgheck).

It is now possible to re-add spaces in label strings where it makes
sense.

Fixes bug #10723.

(cherry picked from commit 5c545573507bbf55f78c294188537c6aff959bc0)