Added support for log stored in CMS_STORAGE.

Added support for custom value stored in CMS_STORAGE.
Added optional css classes addition to CMS_BLOCK output.
Refactored storage, to manage node from node module code only (or mostly).

TODO: improved view for a cms node, for now hardcoded.

src/modules/cms_module.e

@@ -36,6 +36,11 @@ feature {CMS_API} -- Module Initialization
 				-- Redefine to process specific module initialization.
 		end
 
+feature {CMS_API} -- Access: API
+
+	module_api: detachable CMS_MODULE_API
+			-- Eventual module api.
+
 feature {CMS_API} -- Module management
 
 	is_installed (api: CMS_API): BOOLEAN