Fix build with later WDKs

Fix build with later WDKs

- Adds alias for GetProjectInfoForReference target to version.vcxproj
    Later kits seemed to have renamed the build target, and will fail without
    this alias target.
- Adds "/fd sha256" to signtool command line
    WDK 20344 and later require binaries signed with a SHA256 file digest, or
    the build outputs are deleted

Signed-off-by: Owen Smith <owen.smith@citrix.com>
- Squash warnings 4061 and 4062 as they lead to a lot of bogus noise.
- Add a somewhat pointless ASSERT for a condition that has already been
  tested to stop the compiler complaining.

Signed-off-by: Paul Durrant <paul@xen.org>