Fix clang warning about the ObjectTreeSourceIf vtable being emitted in every translation unit.
Summary: Pure interfaces don't get treated well by C++ compilers, better have a .cpp file for the dtor. This required moving the header to one of the actual libs (viewer, since it's only used there). Test Plan: Compiles Reviewers: knauss, #kde_pim Reviewed By: knauss, #kde_pim Subscribers: knauss Differential Revision: https://phabricator.kde.org/D1376
Showing with 130 additions and 25 deletions