Shorten the "repr" of the code plugin
Mark render_placeholder() and render_content_items() output as safe.

Allow the content to be easily used in rendering plugins.
Fix escaping slot name in templates
Add sharedcontent plugin

Instead of solving this issue at the placeholder level,
a `SharedContent` model acts as host for a `PlaceholderField`,
et voila, the thing is working already! :)
Add south migrations for sharedcontent plugin.
Merge branch 'master' of git://github.com/edoburu/django-fluent-contents