[SDL] Bug? DoubleBuf+Windows+Windowed

[Sam Lantinga]

> It appears that doublebuff does not work on windows when in windowed mode.
> The following code has been tested on Windows and Linux.
> On Linux it works as expected, but in Windows it draws to the physical
> screen even though no call has been made to update it.

This has been reported before.  I'll look into it if I can.

See ya,
	-Sam Lantinga, Software Engineer, Blizzard Entertainment