moved wsf_extension inside wsf/extension as wsf/wsf_extension.ecf

added wsf/session as wsf/wsf_session.ecf
In descendants of WSF_HANDLER , we can keep the result of new_mapping as WSF_ROUTER_MAPPING

library/server/wsf/session/wsf_session_factory.e

@@ -0,0 +1,16 @@
+note
+	description: "Summary description for {WSF_SESSION_FACTORY}."
+	author: ""
+	date: "$Date$"
+	revision: "$Revision$"
+
+deferred class
+	WSF_SESSION_FACTORY [G -> WSF_SESSION]
+
+feature -- Access
+
+	new_session (req: WSF_REQUEST; a_reuse: BOOLEAN; m: WSF_SESSION_MANAGER): G
+		deferred
+		end
+
+end