Visual Studio Projects: Fix and update.

* Fix Visual C++ projects for glibmm and giomm as some
  source files are needed but missed and also remove the
  tls* sources from the giomm project as they are not for
  the 2.36 release cycle so that these libraries can be
  properly built

* Fix the projects on how they should locate the libsigc++
  headers, notably the sigc++config.h header file.