Added support for path_aliases.

Refactored CMS_MODULE.router (..): WSF_ROUTER design,
  to create only one router object of type CMS_ROUTER.
Added optional CMS_NODE.link: CMS_LOCAL_LINK
Reviewed permissions related to node module.
Refactor and add CMS_STORAGE_SQL(_BUILDER) abstractions
   for implementation relying only on SQL statements.
Factorized sql builder initialization (to work for sqlite and mysql storage builders).
Added CMS_RESPONSE.formatted_string (a_text: READABLE_STRING_GENERAL; args: TUPLE): STRING_32
Added function "translation", but not implemented for now.
Updated indexing notes and comments.
Code cleaning.

src/persistence/user/cms_user_storage_null.e

@@ -0,0 +1,79 @@
+note
+	description: "Summary description for {CMS_USER_STORAGE_NULL}."
+	author: ""
+	date: "$Date$"
+	revision: "$Revision$"
+
+deferred class
+	CMS_USER_STORAGE_NULL
+
+inherit
+	CMS_USER_STORAGE_I
+
+feature -- Access: user
+
+	has_user: BOOLEAN
+			-- Has any user?
+		do
+		end
+
+	users: LIST [CMS_USER]
+		do
+			create {ARRAYED_LIST [CMS_USER]} Result.make (0)
+		end
+
+	user_by_id (a_id: like {CMS_USER}.id): detachable CMS_USER
+		do
+		end
+
+	user_by_name (a_name: like {CMS_USER}.name): detachable CMS_USER
+		do
+		end
+
+	user_by_email (a_email: like {CMS_USER}.email): detachable CMS_USER
+		do
+		end
+
+	is_valid_credential (l_auth_login, l_auth_password: READABLE_STRING_32): BOOLEAN
+		do
+		end
+
+feature -- Change: user
+
+	new_user (a_user: CMS_USER)
+			-- Add a new user `a_user'.
+		do
+			a_user.set_id (1)
+		end
+
+	update_user (a_user: CMS_USER)
+			-- Update user `a_user'.
+		do
+		end
+
+
+feature -- Access: roles and permissions
+
+	user_role_by_id (a_id: like {CMS_USER_ROLE}.id): detachable CMS_USER_ROLE
+		do
+		end
+
+	user_roles_for (a_user: CMS_USER): LIST [CMS_USER_ROLE]
+			-- User roles for user `a_user'.
+			-- Note: anonymous and authenticated roles are not included.
+		do
+			create {ARRAYED_LIST [CMS_USER_ROLE]} Result.make (0)
+		end
+
+	user_roles: LIST [CMS_USER_ROLE]
+		do
+			create {ARRAYED_LIST [CMS_USER_ROLE]} Result.make (0)
+		end
+
+feature -- Change: roles and permissions		
+
+	save_user_role (a_user_role: CMS_USER_ROLE)
+		do
+		end
+
+end