porting shell from nuget to local

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

@@ -0,0 +1,19 @@
+using System;
+
+namespace Standard
+{
+	[Flags]
+	internal enum NIF : uint
+	{
+		MESSAGE = 1u,
+		ICON = 2u,
+		TIP = 4u,
+		STATE = 8u,
+		INFO = 16u,
+		GUID = 32u,
+		REALTIME = 64u,
+		SHOWTIP = 128u,
+		XP_MASK = 59u,
+		VISTA_MASK = 251u
+	}
+}