- Improve encoding/decoding of parameters and return values:
  - Encode "native" parameters and return values with Solidity ABI.
  - Correctly decode parameters to "create" calls.
  - Use the correct (ish) output for "create" calls.
  - Handle all forms of "create".
- Make robust with respect to reverts:
  - Use the actor ID/address from the trace instead of looking it up in
    the state-tree (may not exist in the state-tree due to a revert).
  - Gracefully handle failed actor/contract creation.
- Improve performance:
  - We avoid looking anything up in the state-tree when translating the
    trace, which should significantly improve performance.
- Improve code readability:
  - Remove all "backtracking" logic.
  - Use an "environment" struct to store temporary state instead of
    attaching it to the trace.
- Fix random bugs:
  - Fix an allocation bug in the "address" logic (need to set the
    capacity before modifying the slice).
  - Improved error checking/handling.

- The top-level type is call/create.
- The action/result is specific to the operation.