v0.10.0

This is my first pass at a significant API improvement. I iterated on it for a
while and this is what I settled on. I look forward to continuing to evolve
this API as I get more feedback and experience with it! Please let me know
what you think!

Breaking Changes

• thinker: stop cancelling actions when they go under Picker thresholds (4c72b3d1)
• stages: Strongly typed stages for BigBrainPlugin (65ca646e)
• builders: Blanket impls for ActionBuilder and ScorerBuilder when Clone (8bed75b5)
• api: rename attach and hide it from docs (6c64df4f)
• choice: return &Choice instead of cloning (a76dcbb6)

Features

• example: update thirst example (edecc4c9)

Bug Fixes

• hierarchy: make sure all the hierarchy stuff is set up properly (372c13e2)
• tests: update tests (94e1b1f6)