Add quick flip buttons to transform docker
Summary:
https://bugs.kde.org/show_bug.cgi?id=352533
Adds vertical flip, horizontal flip, clockwise rotate and counter-clockwise rotate buttons to the free transform docker widget.
Reviewers: Krita, dkazakov
Reviewed By: Krita, dkazakov
Subscribers: dkazakov
Differential Revision: https://phabricator.kde.org/D2127