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.

library/persistence/mysql/src/cms_storage_mysql_builder.e

@@ -1,6 +1,6 @@
 note
 	description: "[
-			Objects that ...
+			Interface responsible to instantiate CMS_STORAGE_MYSQL object.
 		]"
 	author: "$Author: jfiat $"
 	date: "$Date: 2015-01-27 19:15:02 +0100 (mar., 27 janv. 2015) $"
@@ -10,7 +10,9 @@ class
 	CMS_STORAGE_MYSQL_BUILDER
 
 inherit
-	CMS_STORAGE_SQL_BUILDER
+	CMS_STORAGE_STORE_SQL_BUILDER
+
+	GLOBAL_SETTINGS
 
 create
 	make
@@ -32,6 +34,12 @@ feature -- Factory
 				create {DATABASE_CONNECTION_MYSQL} conn.login_with_connection_string (l_database_config.connection_string)
 				if conn.is_connected then
 					create Result.make (conn)
+					set_map_zero_null_value (False)	--| This way we map 0 to 0, instead of Null as default.
+					if Result.is_available then
+						if not Result.is_initialized then
+							initialize (a_setup, Result)
+						end
+					end
 				end
 			end
 		end