build: Retarget AppVeyor build to VS2013
build: Retarget AppVeyor build to VS2013

Change-Id: I88665dadbac75695034a731412984edbecbf988f

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools