Added

• Add flake8 extension to restrict import alias. (improvement)
• Add developer docs on getting started, testing, and StackStorm integration. (improvement)

Changed

• Refactor concept of task flow to workflow and task state. (improvement)
• Restrict ctx function from returning internal vars. (improvement)

Fixed

• Fix conductor performance for complex workflow definition. (bug fix)
• Fix overwritten context variables on task join. (bug fix)
• Fix with items task stuck in running when item(s) failed. (bug fix)
• Fix task status for various scenarios on with item task. (bug fix)
• Fix return value of item that evaluate to false. (bug fix)
• Fix workflow stuck in resuming when pending task has transition error. (bug fix)