Add a utility for dealing with compressed files
Add the compressed test fixtures
Add a test for opening right away.
Add more tests
Add support for compressing too.
Update 'missing executable' to RuntimeError

If you're missing the 'xz' or 'lzma' binary, we now raise
RuntimeError instead of ValueError.
Add a helper to compress an existing raw file.

The 'compress_from' function lets you compress and optionally
remove an existing file.
Support multiple decompression types in job.py
Raise exception on unknown compression type.

Also cleanup comments and long lines.
Add a test for unknown compression type.
Use CompressedFile in process incoming.
Merge branch 'master' into add_xz_support

Conflicts:
	mapreduce/job.py
Merge branch 'master' into add_xz_support
Add some basic Compression benchmarks
Add support for "compression level"
Merge pull request #65 from mozilla/add_xz_support

Add xz support