Use LightTransaction

With https://github.com/iov-one/iov-core/pull/975 merged, we should do the following BlockchainConnection changes:

• Create getTransaction: (id: TransactionId) => Promise<ConfirmedTransaction | FailedTransaction>;. This can later be used when clicking on transaction details from a transactions list. With the result of that, it should be possible to verify the signature locally.
• Change interface to searchTx(query: TransactionQuery): Promise<ReadonlyArray<LightTransaction | FailedTransaction>>
• Change interface to listenTx(query: TransactionQuery): Stream<LightTransaction | FailedTransaction>
• Change interface to liveTx(query: TransactionQuery): Stream<LightTransaction | FailedTransaction>

[webmaster128]

Definitely LightTransaction in these cases rather than ConfirmedTransaction<LightTransaction>?

Nope, my fault. ConfirmedTransaction<LightTransaction> is most likely the way to go. Feel free to do a plausibility check and error correction on the description above. It was more a sketch of the direction than a careful API design.

[webmaster128]

watchSwaps

As a quick and dirty solution, I’d call getTransaction for every liveTx event. This can easily be done as long as we do not have long lists of atomic swaps. This way, we can postpone the question.