Changed extract_image_chips() slightly so that it can take non-resizable images

like cv_image as input.

dlib/image_transforms/interpolation.h

@@ -1621,7 +1621,7 @@ namespace dlib
         }
 
         // now make an image pyramid
-        dlib::array<image_type1> levels(max_depth);
+        dlib::array<image_type2> levels(max_depth);
         if (levels.size() != 0)
             pyr(img,levels[0]);
         for (unsigned long i = 1; i < levels.size(); ++i)