libvpx

vpxdec.sh: Refactor vpxdec().

- Split vpxdec wrapper function into vpxdec() and vpxdec_pipe().
- Remove hard coded --noblit and --summary arguments from
  the wrappers in favor of shifting off the first argument (the
  input file) and passing all remaining parameters to vpxdec.
- Add --noblit and --summary args to existing tests, and update the
  pipe input test to use vpxdec_pipe().

Change-Id: Ia390a9990eace793058b3603ada733fb878eb78c