fixing #467 and correcting image sharpening on PHP 7.0 with GD

admin/include/image.class.php

@@ -301,10 +301,9 @@ class pwg_image
 
     for ($i=0; $i<3; $i++)
     {
-      $line = & $matrix[$i];
       for ($j=0; $j<3; $j++)
       {
-        $line[$j] /= $norm;
+        $matrix[$i][$j] /= $norm;
       }
     }