* Historically there was no bindpoint mapping so it was convenient to
just pad the cbuffers array so that the elements in it were indexed by
their bind point. It doesn't make any sense anymore especially with
D3D12's bind model, so just remove it and roll bind points into a
struct member.
* We make shaders into fake resources with IDs, so they can be
identified individually (for replacement, fetching reflection data,
and things like that). This is a little but ugly but worth it for the
simplicity it will provide everywhere else.
baldurk