fix: check for wallet tx batching support

lib/plugins/wallet/bitcoincashd/bitcoincashd.js

@@ -129,11 +129,17 @@ function cryptoNetwork (account, cryptoCode, settings, operatorId) {
     .then(() => parseInt(rpcConfig.port, 10) === 18332 ? 'test' : 'main')
 }
 
+function supportsBatching (account, cryptoCode) {
+  return checkCryptoCode(cryptoCode)
+    .then(() => _.isFunction(sendCoinsBatch))
+}
+
 module.exports = {
   balance,
   sendCoins,
   newAddress,
   getStatus,
   newFunding,
-  cryptoNetwork
+  cryptoNetwork,
+  supportsBatching
 }