The GetVersionEx function has been deprecated since Windows 8.1.
VerifyVersionInfo exists at least since Windows 2000.
This fixes warnings about use of deprecated functions in MSVC.
Within I420 (as the decoder outputs), the first chroma plane is
U and the second is V, and similarly, in NV12, the chroma components
are written in the order U, V.
This doesn't have any practical effect, it only makes the
variable naming while it previously was misleading.