Add missing DirectComposition method to create Target from `Device`

[prasannavl]

This method is the only way to create a Target in Windows 8, which doesn't have DesktopDevice. And this method is unfortunately missing.

[andrewst]

Target.cs(31,18): error CS7036: There is no argument given that corresponds to the required formal parameter 'target' of 'Device.CreateTargetForHwnd(IntPtr, RawBool, out Target)' must be

      public static Target FromHwnd(Device device, IntPtr hwnd, bool topmost)
      {
         Target target;
         device.CreateTargetForHwnd(hwnd, topmost, out target);
         return target;
      }

[prasannavl]

@andrewst, thanks. I have to apologize for that. It was one awful sleepy and hasty commit. Its fixed now.

[xoofx]

Thanks