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.
Added CMS_NODE_TYPE as descendant of CMS_CONTENT_TYPE,
in case we have content which is not a node in the future.
(probably useless, but for now, this extra abstraction is harmful)
Moved all node related code under node module cluster.
Applied comments from Javier Velilla.
Code cleaning.
but this is an example about on to add a new content type, and support it.
Fixed new node form workflow.
The current state is not final, it requires many changes, but for now, it implements a node editing workflow.
