porting shell from nuget to local

src/Shared/Microsoft.Windows.Shell/Standard/DWMFLIP3D.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace Standard
+{
+	internal enum DWMFLIP3D
+	{
+		DEFAULT,
+		EXCLUDEBELOW,
+		EXCLUDEABOVE
+	}
+}