These files will make it possible to start working with the 64-bit version on Windows.

The GUID's of the x64 project files are the same as their ia32 counterparts, but that does not matter as they will never be used in the same solution.

Added a temporary #error when building 64-bit version on Windows.
Review URL: http://codereview.chromium.org/171111

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2711 ce2b1a6d-e550-0410-aec6-3dcde31c8c00