The "dixie" project will be a rewrite of much of the VP8 decoder core.
Some of the goals are:

  * Increase speed by paying more attention to data locality and
    cache layout, and by eliminating redundant work in general.

  * A different approach to multithreading, to treat all threads as
    equal and working on larger work units than a single MB.

  * Expose more of the bitstream to the application, essentially
    creating a vp8 parser utility. This could be useful for analyzing
    the complexity of a stream, to help set conformance points.

  * If the above goals are met successfully, replace the reference
    decoder.

For those interested in the etymology of the term "dixie:"
  decoder2 -> dx2 -> dxii -> dixie

Change-Id: I4ef0832b62ea96e9cfa1906c4a77f4b51e0c62d6