add README caveat and add extra headers
txoutsmap -> prevtxoutsmap

Clarify that the "txouts" being referred to are actually "previous txouts",
i.e. the outputs connect to the input of the transaction being built or
verified.
update bitcoinjs-lib copyright to latest

The BitcoinJS developers have updated the LICENSE file for bitcoinjs-lib. This
updates the copyright notice here to reflect their update.
support building scripts from common types

scripthash (a.k.a. p2sh addresses) and pubkeyhash (a.k.a. normal bitcoin
addresses)
addToAddress

This convenient method is to add new outputs to your transaction.