fix: check for wallet tx batching support

lib/plugins/wallet/geth/base.js

@@ -29,7 +29,8 @@ module.exports = {
   newFunding,
   privateKey,
   isStrictAddress,
-  connect
+  connect,
+  supportsBatching
 }
 
 function connect (url) {
@@ -222,3 +223,8 @@ function newFunding (account, cryptoCode, settings, operatorId) {
         }))
     })
 }
+
+function supportsBatching (account, cryptoCode) {
+  return checkCryptoCode(cryptoCode)
+    .then(() => _.isFunction(sendCoinsBatch))
+}