Converted test_item.py to use py.test's tmpdir.
Split test_ia_download.py's single test up, and converted it to use py.test's tmpdir.
Changed test_ia_mine.py to use a tempdir, broke up the monolithic test into many.
Broke up test_api.py into more test, and changed a few to use tmpdir.
Broke test_config.py up into many tests. Used tmpdir when writing files.
Changed test_session.py to use tmpdir.
Split test_ia_list.py into a few tests.
Wrapped the test_ia_metadata.py tests requiring authorization in a class, and split them up.
split test_ia_search.py into two tests.
Changed mark in test_ia_upload.py to be on the whole file, and split the individual tests.
Added back exporting the keys in bash to how to supply the S3 keys.