Port ClangClassHelper to also fill the include_files var
Summary:
The "included_files" variable should contain the include directive arguments
for the base classes of the created class.
Reviewers: KDevelop, mwolff, kfunk
Reviewed By: KDevelop, kfunk
Subscribers: kfunk, kdevelop-devel
Differential Revision: https://phabricator.kde.org/D4430