v3.3.1

Bug Fixes and Other Changes

• Revert "change: stream stderr even when capture_error is True"
• Use shlex.quote to construct bash command
• Relax dependencies version requirements
• Extract module to correct location in download_and_install
• Upgrade psutil

Testing and Release Infrastructure

• Fix cleanup with requirements.txt functional tests
• create init.py file for Python 2 import of protobuf during tests (#260)
• Mark intermediate_output functional tests as xfail if not run on Linux