Barrier for better sync

This release includes a Barrier closed until a tx arrives through ZMQ interface to be sure that no txs are left to be retransmitted to the destination node.
https://zguide.zeromq.org/docs/chapter1/
search for "the subscriber will always miss the first messages that the publisher sends"

Also a bug related to source/destination authentication (user&passwd vs cookie) has been solved.

Cookie authentication

This release adds cookie authentication to use bitcoin rpc connections.

ZMQ Interface

This release adds a ZMQ interface to listen new txs while executing, and thus, reduce the tx gap between mempools.

First release

First Release