check-vulkan: Improve Vulkan driver identification

• check-vulkan: Rename VulkanPhysicalDeviceProperties to Renderer

  Otherwise, it's easy to mistake it for a Vk-prefixed struct from the Vulkan API.

• check-vulkan: Pass around more state as fields in the Renderer object

• check-vulkan: Fix most of the memory leaks

• check-vulkan: Add a type-safe wrapper for vkGetInstanceProcAddr

• check-vulkan: Use Vulkan 1.2 if possible

• check-vulkan: Tell our caller the raw (numeric) driver version

  The driver-version field interprets this as being in the same encoding as the apiVersion, but that's not really correct.

• check-vulkan: Produce more information about the driver in use

• graphics: Try to form a better version number from detailed info

Resolves: #79 (closed)