Added original SDK code for Alien Swarm.

game/server/nav_mesh_factory.cpp

@@ -0,0 +1,25 @@
+//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//
+//=============================================================================//
+// NavMeshFactory.cpp
+// Factory to create the NavMesh singleton
+// Author: Michael S. Booth, June 2005
+
+#include "cbase.h"
+#include "nav_mesh.h"
+
+
+
+// memdbgon must be the last include file in a .cpp file!!!
+#include "tier0/memdbgon.h"
+
+CNavMesh *NavMeshFactory( void )
+{
+
+
+	return new CNavMesh;
+}