Add support for changing the HintWindow and HintWindowClass at runtime.
Add support for changing the HintWindow and HintWindowClass at runtime.

It now correctly frees the old hintwindow and recreates it with whatever
the new hintwindowclass is.

wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI