Moved content_types and content_type_webform_managers from CMS_RESPONSE to CMS_API.
Updated the way to output content (node, ...) to html page.
See CMS_CONTENT_TYPE_WEBFORM_MANAGER.append_cointent_as_html_to (...).
Added notion of "teaser" (short version of the content), as opposed to full content.
One can use CMS_API.html_encoder ... when possible, same for `formats', ...
Added bridge from CMS_MODULE_API to CMS_API's encoders.
Added new CMS_TAXONOMY_HOOK used to retrieve list of content associated with a specific term.
Moved up to CMS_RESPONSE a few features which was available only in specific descendants.
Added /taxonomy/term/{termid} implementation.
Updated node web form, to support taxonomy editing if allowed (specific support for CMS_VOCABULARY.is_tags: BOOLEAN).
Added notion of required or optional module dependencies.
