This reverts commit 2ee447fb5f.
That commit introduced a regression (#21882) and didn't really
do what it was supposed to: while it did delay the evaluation
of lazy objects passed to mark_safe(), they weren't actually
marked as such so they could end up being escaped twice.
Refs #21882.
The idea is that if an object implements __html__ which returns a string this is
used as HTML representation (eg: on escaping). If the object is a str or unicode
subclass and returns itself the object is a safe string type.
This is an updated patch based on jbalogh and ivank patches.
See documentation in templates.txt and templates_python.txt for how everything
works.
Backwards incompatible if you're inserting raw HTML output via template variables.
Based on an original design from Simon Willison and with debugging help from Michael Radziej.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@6671 bcc190cf-cafb-0310-a4f2-bffc1f526a37