Table alterations in SQLite require creating a new table and copying
data over from the old one. This change ensures that no Django model
ever exists with the temporary table name as its db_table attribute.

Thanks aruseni for the report.

Thanks to Bas Peschier for pointing this out. Refs #23804.

Thanks Pakal and Claude.

This patch does three major things:

* Merges the django.template.debug implementation into django.template.base.

* Simplifies the debug implementation.

  The old implementation copied debug information to every token and node.
  The django_template_source attribute was set in multiple places, some
  quite hacky, like django.template.defaulttags.ForNode.

  Debug information is now annotated in two high-level places:

  * Template.compile_nodelist for errors during parsing
  * Node.render_annotated for errors during rendering

  These were chosen because they have access to the template and context
  as well as to all exceptions that happen during either the parse or
  render phase.

* Moves the contextual line traceback information creation from
  django.views.debug into django.template.base.Template. The debug views now
  only deal with the presentation of the debug information.

This is a security fix; disclosure to follow shortly.

This is a security fix; disclosure to follow shortly.

Thanks Tim Graham for the review.

Thanks Carl Meyer for the report and Tim Graham for the review.

Tests were using an undocumented keyword argument for easily overriding
script prefix while reversing. This is now changed into a test utility
which can be used as decorator or context manager.

Strings are frozen in anticipation of the Django 1.8 release.
Forward port of 1cd2584c from stable/1.8.x

The only one translatable string will be handled in the core catalog.
Forward port of 1bb712d7 from stable/1.8.x

Thanks Pascal Chambon for the initial patch.