... in many places where the function call will later need to be between
modules (or libraries, or the executable) and the annotation will be a necessity
to keep the linkage working on Windows.
That's all that this sweeping commit does.
... instead define new base classes in src/commands that those other
windows can inherit. The classes have nothing but a virtual destructor. This
lets CommandManager use dynamic_cast to detect the special windows.
See commits cbfde23 and 68e4bf6 which added the #include directives