2.5.2 (unstable):

* Remove useless headers:
    sigc++/class_slot.h
    sigc++/hide.h
    sigc++/method_slot.h
    sigc++/object.h
    sigc++/object_slot.h
    sigc++/retype.h
  Some of these still have equivalents in sigc++/adaptors/
  (Kjell Ahlstedt, Murray Cumming) Bug #752560
* C++11: Replace deprecated std::auto_ptr by std::unique_ptr.
  (Kjell Ahlstedt)
* C++11: Use std::is_base_of<> instead of our sigc::is_base_and_derived<>,
  removing sigc::is_base_and_derived<>.
  (Kjell Ahlstedt, Murray Cumming) Bug #752560
* C++11: Use of range-based for loops.
  (Murray Cumming)
* C++11: Use of the auto keyword.
  (Murray Cumming)
* C++11: Use of nullptr instead of 0.
  (Murray Cumming)
* sigc++/slot.h: Use a regular .h file instead of generating it
  from an .m4 file. Bug #752560
  (Kjell Ahlstedt)
* Visual Studio Builds: Move 2010 Projects to 2012 to support C++11.
  (Chun-wei Fan)
* Use -Wformat-security and -Wshadow with --enable-warnings=fatal.
  (Murray Cumming)