'tests'

Add tests module.
Copyright notice

Add copyright notice to 'test_containers'.
'side_effect_containers' package

Add 'side_effect_containers' package directory.

Add 'containers' module.

All tests pass.
Docstrings

Clean up and revise documentation strings for each container class.
Merge branch 'dev/work' into develop
Release 1.0

Update version number.

Update changelog.

Add copyright notice to package '__init__.py' file.
Merge branch 'release-1.0'