`@0x/contracts-erc20`: Move `LibERC20Token` in. `@0x/contracts-erc20`: Use `LibBytes` and `LibRichErrors` in `LibERC20Token`. `@0x/contracts-erc20`: Use `verifyEventsFromLogs` in `LibERC20Token` unit tests.
`@0x/contracts-erc20`: Move `LibERC20Token` in. `@0x/contracts-erc20`: Use `LibBytes` and `LibRichErrors` in `LibERC20Token`. `@0x/contracts-erc20`: Use `verifyEventsFromLogs` in `LibERC20Token` unit tests.