Add INVALID_FILE_ATTRIBUTES to core.sys.windows.windows

It is used by `core.sys.windows.windows.GetFileAttributesW` and `GetFileAttributesA`.

I could not find the official document about the value of `INVALID_FILE_ATTRIBUTES` and I found it only in [the comment of the document of GetFileAttributes](http://msdn.microsoft.com/en-us/library/windows/desktop/aa364944(v=vs.85).aspx).

Related issue: D-Programming-Language/phobos#2496