Fixed an #include statement so that it works even if you don't

specify an include path argument to your compiler.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402569

dlib/matrix/matrix_utilities.h

@@ -13,7 +13,7 @@
 #include "../stl_checked.h"
 #include <vector>
 #include <algorithm>
-#include "dlib/std_allocator.h"
+#include "../std_allocator.h"