`@0x/contracts-staking`: Convert all rewards to WETH.
`@0x/contracts-staking`: Style changes.
`@0x/contracts-staking`: Address misc. review comments.
`@0x/contracts-staking`: Make `LibFractions` scaling a separate step.
`@0x/contracts-staking`: Rename `delegator_reward_balance_test.ts` -> `delegator_reward_test.ts`.
`@0x/contracts-staking`: Last call before rebasing against 3.0.