Renamed node_api and node_storage by blog_api and blog_storage in related CMS_BLOG_* classes. Mainly to avoid confusion with NODE_ classes.

Merged CMS_BLOG_CONFIG with CMS_BLOG_API.
In CMS_BLOG_API, prefer argument of type CMS_USER, rather than using directly user id.
Added a CMS_EDITOR_CONTENT_FORMAT for now, to be the format editable by the WYSIWYG editor.
Added CMS_MODULE.is_initialized: BOOLEAN to equip router, and module_api with expected preconditions.

Fixed typo, especially in log output.
Corrected a few routine names such as add_authors that should not be a function according to its name.
Converted various function returning html content, to procedure appending html content to an output string to minimize temporary string object creation.
Cosmetic: added spaces to make code easier to read, and indentation.

modules/node/cms_node_api.e

@@ -212,7 +212,6 @@ feature -- Access: Node
 			Result := node_storage.nodes
 		end
 
-
 	recent_nodes (a_offset, a_rows: INTEGER): LIST [CMS_NODE]
 			-- List of the `a_rows' most recent nodes starting from  `a_offset'.
 		do