MemorySessionStore: Session class added

MemorySessionStore$Session: clientSession field added
MemorySessionStore#pendingAck: secondPhaseStore & inflightStore &
inboundFlightMeessageToGuid added

ClientSession#cleanup missed these messages
SubscriptionsDirectoryTest: fixed
SessionsStore#dropInFlightMessagesInSession: changed to cleanSession

mapdb_storage/src/main/java/io/moquette/persistence/mapdb/MapDBSessionsStore.java

@@ -323,9 +323,18 @@ class MapDBSessionsStore implements ISessionsStore, ISubscriptionsStore {
     }
 
     @Override
-    public void dropInFlightMessagesInSession(String clientID) {
+    public void cleanSession(String clientID) {
+        // remove also the messages stored of type QoS1/2
+        LOG.info("Removing stored messages with QoS 1 and 2. ClientId={}", clientID);
         m_secondPhaseStore.remove(clientID);
         outboundFlightMessages.remove(clientID);
+        m_inFlightIds.remove(clientID);
+
+        LOG.info("Wiping existing subscriptions. ClientId={}", clientID);
+        wipeSubscriptions(clientID);
+
+        //remove also the enqueued messages
+        dropQueue(clientID);
     }
 
     static String inboundMessageId2MessagesMapName(String clientID) {