Log miner fee (#237)

* Get miner fee written in some wallet plugins

* Return txid and fee for geth. possible problem with txid (zero hash on pending transaction)

* bitgo fee return

* Wallet apis fees save in cryptoAtoms

lib/plugins/wallet/bitcoincashd/bitcoincashd.js

@@ -1,3 +1,4 @@
+const _ = require('lodash/fp')
 const jsonRpc = require('../../common/json-rpc')
 
 const BN = require('../../../bn')
@@ -41,6 +42,14 @@ function sendCoins (account, address, cryptoAtoms, cryptoCode) {
 
   return checkCryptoCode(cryptoCode)
     .then(() => fetch('sendtoaddress', [address, coins]))
+    .then((txId) => fetch('gettransaction', txId))
+    .then((res) => _.pick(res, ['fee', 'txid']))
+    .then((pickedObj) => {
+      return {
+        fee: BN(pickedObj.fee).abs().shift(unitScale).round(),
+        txid: pickedObj.txid
+      }
+    })
     .catch(err => {
       if (err.code === -6) throw new E.InsufficientFundsError()
       throw err