export/hazard:

PEP8/pyflakes cleanup.
export/risk:

s/target_dir/target/g
utils:

Added FileWrapper context manager util class.
export/hazard:

Updated a few isinstance checks (on file paths) to check if the var is
either basestring or buffer.
export/risk:

Refactored the way export targets are handled. There is no longer tight
coupling with filepaths/the filesystem. Now, we can specify any kind of
target, either a filepath or a file-like object.
tests/export/risk_test:

Updated tests per some refactoring to the risk export implementation.