Fixed some typos

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%403050

dlib/image_keypoint/hessian_pyramid_abstract.h

@@ -27,7 +27,7 @@ namespace dlib
                 This object is an implementation of the fast Hessian pyramid 
                 as described in the paper: 
                    SURF: Speeded Up Robust Features
-                   By Herbert Bay1 , Tinne Tuytelaars2 , and Luc Van Gool12
+                   By Herbert Bay, Tinne Tuytelaars, and Luc Van Gool
 
                 This implementation was also influenced by the very well documented
                 OpenSURF library and its corresponding description of how the fast

dlib/image_keypoint/surf_abstract.h

@@ -18,7 +18,7 @@ namespace dlib
 
         This is the original paper which introduced the algorithm:
             SURF: Speeded Up Robust Features
-            By Herbert Bay1 , Tinne Tuytelaars2 , and Luc Van Gool12
+            By Herbert Bay, Tinne Tuytelaars, and Luc Van Gool
 
         This paper provides a nice detailed overview of how the algorithm works:
             Notes on the OpenSURF Library by Christopher Evans