Reinstate stop function

lib/noaa_apt_sink_impl.cc

@@ -127,12 +127,16 @@ namespace gr
     }
 
     noaa_apt_sink_impl::~noaa_apt_sink_impl () {
+
+    }
+    bool
+    noaa_apt_sink_impl::stop(){
         if(!d_image_received){
         	write_image(d_full_image, d_filename_png);
         }
+        return true;
     }
 
-
     void noaa_apt_sink_impl::set_pixel (size_t x, size_t y, float sample) {
         // Adjust dynamic range, using minimum and maximum values
         sample = (sample - f_min_level) / (f_max_level - f_min_level) * 255;

lib/noaa_apt_sink_impl.h

@@ -77,7 +77,8 @@ namespace gr
       work (int noutput_items, gr_vector_const_void_star &input_items,
             gr_vector_void_star &output_items);
 
-
+      bool
+	  stop();
     private:
 
         /*