message: fix network property fetch for transaction builder
  Summary:
  Merge branch 'master' into txb_network_fix
  # Conflicts:
  #	src/transactionBuilder.js
  Reviewers: kevin, robert
  Subscribers: ben
diff: @@ -821,7 +821,7 @@ exports.signTransaction = function(params) {
  hdPath = bitcoin.hdPath(rootExtKey);
  }
  - const txb = bitcoinCash.TransactionBuilder.fromTransaction(transaction, rootExtKey.keyPair.network);
  + const txb = bitcoinCash.TransactionBuilder.fromTransaction(transaction, _.get(rootExtKey, 'keyPair.network', bitcoin.networks.bitcoin));
  for (let index = 0; index < txb.tx.ins.length; ++index) {
  const currentUnspent = params.unspents[index];
  