Rewrite word wrapping for gettext entries
Old algorithm works not right as expected - if text have unintended newlines, lokalize wraps them as required, and result goes not identical as vanilla gettext.
This produce some noize when commiting PO catalogs into git.
- Fix issue when whitespace appears as leading character in next string instead of trailing in previous.
- New algorithm removes all newlines and then add them where they are really needed, after that goes standard word wrapping with nice max 78-wide lines.
See also https://bugs.kde.org/show_bug.cgi?id=380007 and https://bugs.kde.org/show_bug.cgi?id=402838, https://phabricator.kde.org/D10009