There are some missing parts from this commit as these are the fairly
clean changes. Missing is building a separate set of pipelines for the
new render pass (might be able to get away from that), OIT heads texture
is flat rather than an array, view matrices aren't set up, and the
fisheye renderer isn't hooked up to the output pass (code exists but is
messy). However, with the missing parts included, testing shows things
mostly working: the cube map is rendered correctly even though it's not
displayed correctly (incorrect view). This has definitely proven to be a
good test for Vulkan's multiview feature (very nice).
Although it works as intended (tested via hacking), it's not hooked up
as the current frame buffer handling in r_screen is not readily
compatible with how vulkan output is handled. This will need some
thought to get working.
When working, this will handle the output to the swap-chain images and
any final post-processing effects (gamma correction, screen scaling,
etc). However, currently the screen is just black because the image
for getting the main render pass output isn't hooked up yet.
