Add sent and received shielded Txs in the transactions tab.

src/senttxstore.h

@@ -0,0 +1,18 @@
+#ifndef SENTTXSTORE_H
+#define SENTTXSTORE_H
+
+#include "precompiled.h"
+#include "mainwindow.h"
+#include "rpc.h"
+
+class SentTxStore {
+public:
+    static QList<TransactionItem> readSentTxFile();
+    static void                   addToSentTx(Tx tx, QString txid);
+
+private:
+    static QString writeableFile();
+    
+};
+
+#endif // SENTTXSTORE_H