Removing unused imports

import sys is not being used anywhere in this file
Changes so circusctl can run on Windows
flake8 fixes
Separate out import tests
Handle case where captured output could not be imported
Merge pull request #693 from scottkmaxwell/run_whats_possible_on_windows

Changes so circusctl can run on Windows
Merge pull request #692 from decklord/patch-1

Removing unused imports
Modify examples
Merge pull request #695 from dongweiming/master

Modify examples
Modify boolean achieve
Modify PEP8 E221
Merge pull request #696 from dongweiming/modify_bool_achieve

Modify boolean achieve
renamed NOTICE to CONTRIBUTORS.txt for clarity
Update CONTRIBUTORS.txt

Add dongweiming to CONTRIBUTORS.txt
Merge pull request #700 from dongweiming/patch-1

Update CONTRIBUTORS.txt
Comment out XXX line.
Merge pull request #703 from igungor/patch-1

Comment out XXX line.