3.19.3: * Require the latest gtkmm and glibmm. * Multi-threaded chapter: Remove warnings about sigc::slots and Glib::Threads::Thread. Because people would use regular lambdas or std::function functors with std::thread in C++11. (Murray Cumming) Bug #755091 * multithread example: Use std::thread, etc, instead of Glib::Threads::*. Because C++11 now has this concurrency API and we should use standard C++ where possible. (Murray Cumming) Bug #755091