use STL were no implicit sharing is required
Summary:
try to move to STL for some parts that don't want any sharing nor
detaching
Test Plan: make && make test
Reviewers: dhaumann
Reviewed By: dhaumann
Subscribers: dhaumann, kwrite-devel, kde-frameworks-devel
Tags: Kate, Frameworks
Differential Revision: https://phabricator.kde.org/D17457