Merge pull request #1346 from toastdriven/ignore-venv

Ignore the venv directory from the contributing docs.
Added basic unit tests for boto.exception.BotoServerError
Fix typo bug in attach_network_interface.  Some PEP8 docstring cleanup.
Added new root certs to cacerts.txt, to provide additional flexibility in the future
Added a regression test for SQS's delete behavior & updated the docs.
Regression test passing, demonstrating ``force_deletion`` no longer has an effect.