v4.0.0

This is a major release with several API changes and an update to use Bitcoin v0.12.0 and requires a database reindex. Bitcore now starts bitcoind as a child process and communicates via ZMQ/RPC, address indexes are now built and queried from Bitcoin directly using a branch with additional indexing options added, more information is at: https://bitcore.io/bitcoin

Please see https://github.com/bitpay/bitcore-node/blob/f72fe82c6037011220bd7936bf3baa263ce59a00/docs/upgrade.md for more details on upgrading.