WIP: Allow cmake to generate projects targeting platforms with the VCTargets outside the default VS install directory.
By adding VCTarget= to the global properties of a project file, you can instruct it to read platform .props and .target files from somewhere else. Unfortunately some projects don't include the global properties and Visual Studio refuses to load them (Fails to find Platform .props/.target files).
Change allows utility objects to pick up global properties (which in theory should have no effect on them).
Also included XboxOne platform cmake files (copies of Windows version).