Create Parsons Mailchimp connector

[SorenSpicknall]

No description provided.

[jburchard]

Initial first pass. This is great. Only some minor changes needed, largely around comments for the documentation.

Also, please add:

• mailchimp.rst file
• mailchimp to the index.rst file. See other classes for examples.
• mailchimp.py import top level __init__.py

[SorenSpicknall]

I added RST documentation in 4b1a3e0, and resolved other specific feedback in additional commits. Could you expand on what you mean by this, though, @jburchard?

mailchimp.py import top level init.py

[jburchard]

Sure.

Just import the class into this file:

[eliotst]

I just had the one comment. As per our conversation, it'd also be good to get some unit tests in before merging. This is great work! Thanks!

[SorenSpicknall]

I added some testing with basic assertions, which we can expand upon down the road, and took care of the remaining feedback items. Ready for re-review.