v0.2.91

What's Changed

• Refactor interpreter and update concurrency terminology by @gabewillen in #10
• Feature/testing by @gabewillen in #11
• Replace 'do_activity' attribute with 'activity' in State class by @gabewillen in #12
• Feature/documentation by @gabewillen in #13

Full Changelog: v0.2.6...v0.2.91