requiring the latest pytest-diffeo
fixing the way that --third-dir gets used by streamcorpus_pipeline_test
fixing  "-i -" for streaming path names over stdin; and causing i to be tested.
introducing fallback_media_type used by guess_media_type
fixing typo in previous update to test_lingpipe that was untested
because --run-integration tests was not being added to
streamcorpus_pipeline_test, and now is.
adding package data back in so that streamcorpus_pipeline_test passes better
adding sphinx docs
adding make target for updating http://streamcorpus.org/