feat: support shielded zec sends

lib/plugins/wallet/zcashd/zcashd.js

@@ -52,11 +52,42 @@ function balance (account, cryptoCode) {
 
 function sendCoins (account, address, cryptoAtoms, cryptoCode) {
   const coins = cryptoAtoms.shift(-unitScale).toFixed(8)
-
+  const checkSendStatus = function (opid) {
+    return new Promise((resolve, reject) => {
+      function checker(timeout) {
+        setTimeout(() => {
+          fetch('z_getoperationstatus', [[opid]])
+            .then(res => {
+              const status = _.get('status', res[0])
+              switch(status) {
+                case 'success': 
+                  resolve(res[0])
+                  break
+                case 'failed': 
+                  reject(res[0].error)
+                  break
+                case 'executing':
+                  if (timeout > 0) {
+                    checker(timeout - 500)
+                  } else {
+                    reject(res)
+                  }
+              }
+            })
+        }, 500)
+      }
+      checker(10000)
+    })
+  } 
   return checkCryptoCode(cryptoCode)
-    .then(() => fetch('sendtoaddress', [address, coins]))
-    .then((txId) => fetch('gettransaction', [txId]))
-    .then((res) => _.pick(['fee', 'txid'], res))
+    .then(() => fetch('z_sendmany', ["ANY_TADDR", [{address, amount: coins}]]))
+    .then(checkSendStatus)
+    .then((res) =>  {
+      return {
+        fee: _.get('params.fee', res),
+        txid: _.get('result.txid', res)
+      }
+    })
     .then((pickedObj) => {
       return {
         fee: BN(pickedObj.fee).abs().shift(unitScale).round(),