Fixed typo in the vector spec.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402828

dlib/geometry/vector_abstract.h

@@ -363,15 +363,6 @@ namespace dlib
         provides a global swap function
     !*/
 
-    template<typename T, long NR>
-    inline void swap (
-        vector<T,NR> & a, 
-        vector<T,NR> & b 
-    ) { a.swap(b); }   
-    /*!
-        provides a global swap function
-    !*/
-
     template<typename T, long NR>
     void serialize (
         const vector<T,NR>& item,