Replace obsolete methods in KFourInLine with non-obsolete ones

Summary: There are some obsolete methods in the current code (qCopy, qSort and setWorldMatrix). This patch replaces them with common replacements (std::copy, std::sort, and setWorldTransform).

Test Plan:

1. Compile and install KFourInLine. There should be no deprecation warnings with Qt 5.13.
2. Run kfourinline. Watch demo, play some games. No visible differences should be observed.

Reviewers: KDE Games, aacid

Reviewed By: aacid

Subscribers: aacid, ognarb, kde-games-devel

Differential Revision: https://phabricator.kde.org/D23297