add release() method

src/utils/refcntr.h

@@ -32,12 +32,18 @@ public:
             (*pcount)++;
         return  *this;
     }
-    ~RefCntr() 
+    void release()
     {
         if (pcount && --(*pcount) == 0) {
             delete rep;
             delete pcount;
         }
+        rep = 0;
+        pcount = 0;
+    }
+    ~RefCntr() 
+    {
+        release();
     }
     X *operator->() {return rep;}
     X *getptr() const {return rep;}