- Remove includes of config.h wrapped by HAVE_CONFIG_H. This
is an obsolete vestige of our libvpx ancestry.
- Change (nearly) all remaining include sites; use proper path
to the include relative to project root instead of ./.
- Correct include order where appropriate.
- Note: This part of this patch is NOT exhaustive. In an
attempt to be conseravative about the impact of this change
I limited ordering and grouping changes to places that
appear extremely unlikely to cause a problem. A more exhaustive
follow up might be appropriate, but this issue can likely be
handled organically from here on out.