Listen for 'confirmation' event to avoid need for waitTransactionFinished

[nick]

Now we're using web3 1.0, we could listen for the confirmation event to avoid the need to waitTransactionFinished. Though there are benefits to having both, such as updating the UI when the transaction has a receipt vs when it is actually confirmed.

Thought I'd bring it up, anyway, as we now have access to a few more convenient APIs.