Release v3.0.0-alpha.6

This is includes some breaking changes from v3.0.0-alpha.4, including:

• Chain classes (Bitcoin, Ethereum, etc.) parameters should be passed in as an object instead of individually, to avoid confusion with how providers and signers are passed in:

Bitcoin(network) ---> Bitcoin({network})
Ethereum(network, {signer, provider}) ---> Ethereum({network, signer, provider})

• The status field on gateway transactions has been removed in favor of checking the statuses of each transaction directly. Switching on tx.status should now instead check tx.in.status, tx.renVM.status and tx.out.status. This change is to push the concept that a gateway transaction is just a bundle of chain transactions (including the RenVM transaction), and because the number of states needing to be enumerated grew too large.

• The status field and event name on TxWaiter and TxSubmitter has been renamed to progress, to avoid confusion between the state of the transaction and its status enum.

• The fee object returns from gateway.fees or renJS.getFees now includes a single variableFee field that replaces the mint and burn fields, and a single fixedFee that replaces the lock and release fields.