Add tx:events method

[fvictorio]

Add a tx:events method that, given some ABIs and a transaction hash, prints all the emitted events, properly parsed when they belong to one of the given ABIs.

Something we need to define: how are the ABIs passed to the command? One option is to do something like:

eth tx:events --abi abi1 --abi abi2 txHash

This should work, but the question is if we should also include the "known ABIs". I mean: if erc20 and erc721 should be included even if you don't specify them.