* It's not particularly scalable and can be brittle to driver changes, and we
can use targeted specific pixel tests to check what we really want - to see if
the output has rendered correctly.
* Overlay tests still check files directly - this is a future refactor to
remove.
* Subresource handling is more consistent - we pass around a struct now that
contains the array slice, mip level, and sample. We remove the concept of
'MSAA textures count samples as extra slices within the real slices' and
internalise that completely. This also means we have a consistent set
everywhere that we need to refer to a subresource.
* Functions that used to be in the ReplayOutput and use a couple of implicit
parameters from the texture viewer configuration are now in the
ReplayController and take them explicitly. This includes GetMinMax,
GetHistogram, and PickPixel.
* Since these functions aren't ReplayOutput relative, if you want to decode the
custom shader texture or the overlay texture you need to pass that ID
directly.
baldurk