Fixed a minor interface usability flaw in the scan_fhog_pyramid. It wasn't

documented that you couldn't change the padding, cell size, or window size
parameters between calls to load() and detect().

dlib/image_processing/scan_fhog_pyramid.h

@@ -115,6 +115,7 @@ namespace dlib
 
             window_width = width;
             window_height = height;
+            feats.clear();
         }
 
         inline unsigned long get_detection_window_width (
@@ -133,6 +134,7 @@ namespace dlib
         )
         {
             padding = new_padding;
+            feats.clear();
         }
 
         unsigned long get_padding (
@@ -150,6 +152,7 @@ namespace dlib
                 );
 
             cell_size = new_cell_size;
+            feats.clear();
         }
 
         unsigned long get_cell_size (

dlib/image_processing/scan_fhog_pyramid_abstract.h

@@ -338,6 +338,7 @@ namespace dlib
                   particular, the size of the window we scan over the HOG feature pyramid
                   is #get_fhog_window_width() by #get_fhog_window_height() HOG cells in
                   size.    
+                - #is_loaded_with_image() == false
         !*/
 
         unsigned long get_detection_window_width (
@@ -386,6 +387,7 @@ namespace dlib
         /*!
             ensures
                 - #get_padding() == new_padding
+                - #is_loaded_with_image() == false
         !*/
 
         unsigned long get_padding (
@@ -415,6 +417,7 @@ namespace dlib
                 - new_cell_size > 0
             ensures
                 - #get_cell_size() == new_cell_size
+                - #is_loaded_with_image() == false
         !*/
 
         inline long get_num_dimensions (