feat: rbf checking in blockcypher plugin

lib/plugins/wallet/bitcoind/bitcoind.js

@@ -126,11 +126,23 @@ function cryptoNetwork (account, cryptoCode) {
     .then(() => parseInt(rpcConfig.port, 10) === 18332 ? 'test' : 'main')
 }
 
+function fetchRBF (txId) {
+  return fetch('getmempoolentry', [txId])
+    .then((res) => _.assign(_.pick(['bip125-replaceable'], res)), { tx_hash: txId })
+    .catch(err => {
+      if (err.code === -5) console.log(`${err.message}`)
+      const result = { tx_hash: txId }
+      result['bip125-replaceable'] = true
+      return result
+    })
+}
+
 module.exports = {
   balance,
   sendCoins,
   newAddress,
   getStatus,
   newFunding,
-  cryptoNetwork
+  cryptoNetwork,
+  fetchRBF
 }