Short wrappers for Draw functins are in vid_render_vulkan.c so the
vulkan context can be passed on to the actual functions. The 2D shaders
are set up similar to those in glsl, but with full 32-bit color (rgba)
support instead of paletted. However, the textures are not loaded yet,
nor is anything bound.
It turned out I needed access to the physical device from a buffer
object, so rather than storing the vulkan logical device directly in
buffer (and other) objects, store the qfv logical device.
