Note that CMS_SETUP provides locations set by default or from configuration file.
Now theme related resources can be found under site/modules/$mod_name/... or site/themes/$theme/modules/...
so only theme related resources can be overriden for now.
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.
