Issue 10469 - Move WinAPI prototypes and enums need by std.process to core.sys.windows.windows

http://d.puremagic.com/issues/show_bug.cgi?id=10469

<del>**Note**: Phobos pull https://github.com/D-Programming-Language/phobos/pull/1371 needs to be pulled together with this.</del>

Related Phobos pull: Phobos pull https://github.com/D-Programming-Language/phobos/pull/1371