implement the proposed snappy framing format

see:
  http://code.google.com/p/snappy/source/browse/trunk/framing_format.txt
      ?spec=svn68&r=55
make the stream compressor automatically choose compression

making the user choose between adding compressed and uncompressed
chunks themselves is a little lame. add some automatic defaults.
add commandline interface
fix suggested stream to stream blocksize
updating README to reflect cmdline usage
upgrade snappy framing format

the framing format changed:
https://code.google.com/p/snappy/issues/detail?id=34
pack/unpack chunk identifiers more efficiently, fix py3
don't mark identifier chunks as skippable
add test for decompression buffering
whoops, forgot to update some docstrings
Added JT Olds to AUTHORS
Merge branch 'master' of https://github.com/felipecruz/python-snappy