* This is kind of a "damned if you do, damned if you don't" situation. If the
cullmode is wrong, having it show up as failures in depth/stencil overlays is
misleading. However if the cullmode is deliberate setting it to no-cull may
ruin the results of those overlays.
* The original behaviour of leaving cullmode as is ends up being a better
tradeoff, since at least when it is misleading you can use the culling overlay
to show the failure there. If culling is disabled it makes depth/stencil
overlays useless in situations with no recourse.
* Also add a test of a depth-clipped triangle to overlay tests
* Built entirely independently of the main renderdoc build (for now).
* Contains python scripts & framework for running tests on a renderdoc build,
which will be run nightly.
baldurk