Fixes #7817 and #9456.

- The include tag now has a 'with' option to include to provide extra context
  vairables to the included template.

- The include tag now has an 'only' option to exclude the current context
  when rendering the included template.

- The with tag now accepts multiple variable assignments.

- The with, include and blocktrans tags now use a new keyword argument format
  for variable assignments (e.g. `{% with foo=1 bar=2 %}`).

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14922 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/topics/db/optimization.txt

@@ -206,7 +206,7 @@ many-to-many relation to User, the following template code is optimal:
 .. code-block:: html+django
 
    {% if display_inbox %}
-     {% with user.emails.all as emails %}
+     {% with emails=user.emails.all %}
        {% if emails %}
          <p>You have {{ emails|length }} email(s)</p>
          {% for email in emails %}