Fix the Visual Studio 2008/2010 Projects

Remove the /vd2 compile-time option, as it causes crashes in the built
binaries, and define a MSVC-compatible getc_unlocked() replacement.

	* MSVC_Net2008/gdkmm/gdkmm.vcproj:
	* MSVC_Net2008/gtkmm/gtkmm.vcproj:
	* MSVC_Net2010/gdkmm/gdkmm.vcxproj:
	* MSVC_Net2010/gtkmm/gtkmm.vcxproj: Remove the /vd2 compile option, as it
	  is not needed and causes crashes in the built code.
	* MSVC_Net2008/demos/gtk-demo/gtk-demo.vcproj:
	* MSVC_Net2010/demos/gtk-demo/gtk-demo.vcxproj: Remove the /vd2
	  compile option, and define a getc_unlocked() replacement suitable
	  for Visual Studio builds.