Hover action on main Window instead of screen corners

[vhanla]

Add hover buttons in any application's window corner and sides, to trigger selected actions.

Show clickable buttons around the main window of an application or children, and let them trigger actions related mainly to the handling of windows like: centering, resizing, moving, etc.

Still in early stages, the hook is working flawlessly but needs more work to do. Might be included in the following releases, but not the near next.