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).
This is the only case where the button's name does not match the
locale's text, the button name being "Ok" and the locale text item being
"OK", fully capitalized.
