protecting c-pointer-handles from being freed twice.

MessengerProj/src/main/java/com/b44t/messenger/MrChat.java

@@ -46,6 +46,7 @@ public class MrChat {
     @Override protected void finalize() throws Throwable {
         super.finalize();
         MrChatUnref(m_hChat);
+        m_hChat = 0;
     }
 
     public native int    getId();

MessengerProj/src/main/java/com/b44t/messenger/MrChatlist.java

@@ -36,6 +36,7 @@ public class MrChatlist {
     @Override protected void finalize() throws Throwable {
         super.finalize();
         MrChatlistUnref(m_hChatlist);
+        m_hChatlist = 0;
     }
 
     public int getCnt() {

MessengerProj/src/main/java/com/b44t/messenger/MrContact.java

@@ -40,6 +40,7 @@ public class MrContact {
     @Override protected void finalize() throws Throwable {
         super.finalize();
         MrContactUnref(m_hContact);
+        m_hContact = 0;
     }
 
     public native String getName();

MessengerProj/src/main/java/com/b44t/messenger/MrLot.java

@@ -41,6 +41,7 @@ public class MrLot {
     @Override protected void finalize() throws Throwable {
         super.finalize();
         MrLotUnref(m_hLot);
+        m_hLot = 0;
     }
 
     public native String getText1();

MessengerProj/src/main/java/com/b44t/messenger/MrMsg.java

@@ -64,6 +64,7 @@ public class MrMsg {
     @Override protected void finalize() throws Throwable {
         super.finalize();
         MrMsgUnref(m_hMsg);
+        m_hMsg = 0;
     }
 
     public int getId() {