Adds functions for executing functions within separate threads without
blocking the user interface, or by blocking the user interface with a
dialog box.
Allows creating a QThread via an std::function. A backward-compatible
alternative to QThread::create for Qt versions older than 5.10 (when it
became available in Qt).
A helper function used with QMetaObject::invokeMethod which allows the
ability to use Qt::DirectConnection if on the Qt UI thread, or
Qt::BlockingQueuedConnection if on another thread to ensure that
regardless of what thread the invokeMethod is called from, that it will
wait until the invoked method has been called.
