Clean up repo for next milestone

[sshine]

This is a short brainstorm on issues that we can focus on in 2021.

• [x] Remove all references to "Dagger" and "daggerc".
• [ ] Fix module imports. (This helps to locate dead code.)
• [ ] Remove dead code.
• [ ] Clean up package.yaml.
• [ ] Remove broken tests in cases where semantics have changed.
• [ ] Set up Continuous Integration
  • [ ] Unit tests (easy to set up; current tests don't give us much)
  • [ ] Integration tests (requires geth_tools or similar gives deterministic results)

[Sword-Smith]

Remove all references to "Dagger" and "daggerc". Fixed in 64642ec6262ffb9f27ccf3cb66502e6bdb3eb230