Added reset to the receiver, computation of power and function for setting arfcn of the receiver
diff --git a/include/gsm/receiver.h b/include/gsm/receiver.h
index c94720d..d5bfa41 100644
--- a/include/gsm/receiver.h
+++ b/include/gsm/receiver.h
@@ -49,6 +49,9 @@
        * creating new instances.
        */
       static sptr make(feval_dd * tuner, int osr, int arfcn);
+      
+      virtual void set_arfcn(int arfcn) = 0;
+      virtual void reset() = 0;
     };
 
   } // namespace gsm