Fix repeated NFT when mining block

src/main/java/pl/mikorosa/dziecoin/gui/MainFrame.java

@@ -197,6 +197,7 @@ public class MainFrame extends JFrame {
             }
 
             transactions.clear();
+            nfts.clear();
 
             howMuchLeftToSpend = bc.getAddressBalance(addr);
 

src/main/resources/META-INF/MANIFEST.MF

@@ -0,0 +1,9 @@
+Manifest-Version: 1.0
+Main-Class: pl.mikorosa.dziecoin.Main
+Class-Path: junit-platform-commons-1.9.2.jar junit-jupiter-5.9.2.jar mys
+ ql-connector-java-8.0.30.jar protobuf-java-3.19.4.jar hamcrest-core-1.3
+ .jar apiguardian-api-1.1.2.jar junit-platform-engine-1.9.2.jar junit-ju
+ piter-engine-5.9.2.jar junit-jupiter-api-5.9.2.jar mysql-connector-java
+ -8.0.30.jar opentest4j-1.2.0.jar commons-csv-1.6.002.jar junit-4.13.2.j
+ ar junit-jupiter-params-5.9.2.jar
+