ffnvcodec: Add nvcodec windows support

Add fetch_and_patch script for ffnvcodec.

fetch_and_patch script copies needed headers to contrib include
directory.

Patch file to adapt ffmpeg configure script for ffnvcodec package
inclusion. On linux pkg_config is used. On windows the files
need to be included manually.

config script includes path for ffnvcodec files and corresponding
flags are set.

Change-Id: Ia9daca2a49316a4373652acb718930d02f85e3f6
Reviewed-by: Philippe Gorley <philippe.gorley@savoirfairelinux.com>