Also, fix up window behaviour... allow dragging it larger and smaller,
disable maximize, and don't allow snapping bigger or smaller than
the user area.

Finally, when r2y tables aren't installed, set the aspect ratio to
xsize x ysize so all the aspect "stuff" works properly.

With this, GDI is now the default output mode for Windows.  Auto
order is now:

X11 -> GDI -> SDL -> Win32 Console or Curses -> ANSI

Now that GDI is self-contained, does not require SDL, and runs in
a window, compile as a Windows application to prevent a console
window from opening then closing at startup.  Win32 console mode
now has to rely on AllocConsole(), which opens a new console
window.  This is likely the best choice anyway since ciolib
absolutely destroys your console settings, so that console is even
less useful than the normal windows console after a utility runs.

Maybe for 2.0 I'll do a Wayland and Core Graphics driver too. :D