2.5.0

• Add support for "shortcodes", that is, function calls embedded in the document source.
• Add a new configuration option to load plugins from a directory.
• Documents which fail to parse don't abort the build any more. Instead, a warning will be printed pointing to the broken document, and the processing will continue.
• Markdown extensions can be configured now. As part of this change, the default output format changed to html5 (previously it was xhtml.)
• Add a new build_context global variable to templates.