[Theora] libtheora 1.0 alpha 6 release

[Ralph Giles]

All,

I'm pleased to announce a new release of the libtheora reference 
implemenation. This is an incremental update over alpha 5, consisting 
primarily of bug fixes and a merge of the encoder optimizations from 
the theora-mmx branch.

Source is available from the usual location:

  http://downloads.xiph.org/releases/theora/

Changes since the 1.0 alpha 5 release:

    * Merge theora-mmx simd acceleration (x86_32 and x86_64)
    * Major RTP payload specification update
    * Minor format specification updates
    * Fix some spurious calls to free() instead of _ogg_free()
    * Fix invalid array indexing in PixelLineSearch()
    * Improve robustness against invalid input
    * General warning cleanup
    * The offset_y member now means what every application thought 
      it meant (offset from the top). This will mean some old files
      (those with a non-centered image created with a buggy encoder)
      will display differently.

SHA-1 checksums:

  0fa7314a432e60c6178a7d98b6408c7a950155ed  libtheora-1.0alpha6.tar.bz2
  93ec6eaccc841581a723c251db06138fd9e783f4  libtheora-1.0alpha6.tar.gz
  c4185656933ff779ce5dba2d211b9ece398d567d  libtheora-1.0alpha6.zip

MD5 checksums:

  ff8d0c112fdab66930acf42c423d2536  libtheora-1.0alpha6.tar.bz2
  0309b6e6da4b3a5e5d27adfc8558a73d  libtheora-1.0alpha6.tar.gz
  b591a1173712eebc2395c9ab5aa4318f  libtheora-1.0alpha6.zip

Thanks to everyone who contributed!