for all Chameleon BFG templates by setting a BFG-related Paster
  ``.ini`` file setting named ``debug_templates``. The exceptions
  raised by Chameleon templates when a rendering fails are sometimes
  less than helpful.  ``debug_templates`` allows you to configure your
  application development environment so that exceptions generated by
  Chameleon during template compilation and execution will contain
  more helpful debugging information.  This mode is on by default in
  all new projects.

No foreigners were harmed in the coding of this feature.

--------

- The ``Configurator.add_view`` method now accepts an argument named
  ``context``.  This is an alias for the older argument named
  ``for_``; it is preferred over ``for_``, but ``for_`` will continue
  to be supported "forever".

- The ``view`` ZCML directive now accepts an attribute named
  ``context``.  This is an alias for the older attribute named
  ``for``; it is preferred over ``for``, but ``for`` will continue to
  be supported "forever".

- The ``Configurator.add_route`` method now accepts an argument named
  ``view_context``.  This is an alias for the older argument named
  ``view_for``; it is preferred over ``view_for``, but ``view_for``
  will continue to be supported "forever".

- The ``route`` ZCML directive now accepts an attribute named
  ``view_context``.  This is an alias for the older attribute named
  ``view_for``; it is preferred over ``view_for``, but ``view_for``
  will continue to be supported "forever".

Documentation and Paster Templates
----------------------------------

- All uses of the ``Configurator.add_view`` method that used its
  ``for_`` argument now use the ``context``argument instead.

- All uses of the ``Configurator.add_route`` method that used its
  ``view_for`` argument now use the ``view_context``argument instead.

- All uses of the ``view`` ZCML directive that used its ``for``
  attribute now use the ``context`` attribute instead.

- All uses of the ``route`` ZCML directive that used its ``view_for``
  attribute now use the ``view_context`` attribute instead.

--------

- The ``Configurator`` object now has two new methods: ``begin`` and
  ``end``.  The ``begin`` method is meant to be called before any
  "configuration" begins (e.g. before ``add_view``, et. al are
  called).  The ``end`` method is meant to be called after all
  "configuration" is complete.

  Previously, before there was imperative configuration at all (1.1
  and prior), configuration begin and end was invariably implied by
  the process of loading a ZCML file.  When a ZCML load happened, the
  threadlocal data structure containing the request and registry was
  modified before the load, and torn down after the load, making sure
  that all framework code that needed ``get_current_registry`` for the
  duration of the ZCML load was satisfied.

  Some API methods called during imperative configuration, (such as
  ``Configurator.add_view`` when a renderer is involved) end up for
  historical reasons calling ``get_current_registry``.  However, in
  1.2a5 and below, the Configurator supplied no functionality that
  allowed people to make sure that ``get_current_registry`` returned
  the registry implied by the configurator being used.  ``begin`` now
  serves this purpose.  Inversely, ``end`` pops the thread local
  stack, undoing the actions of ``begin``.

  We make this boundary explicit to reduce the potential for confusion
  when the configurator is used in different circumstances (e.g. in
  unit tests and app code vs. just in initial app setup).

  Existing code written for 1.2a1-1.2a5 which does not call ``begin``
  or ``end`` continues to work in the same manner it did before.  It
  is however suggested that this code be changed to call ``begin`` and
  ``end`` to reduce the potential for confusion in the future.

- All ``paster`` templates which generate an application skeleton now
  make use of the new ``begin`` and ``end`` methods of the
  Configurator they use in their respective copies of ``run.py`` and
  ``tests.py``.

Documentation
-------------

- All documentation that makes use of a ``Configurator`` object to do
  application setup and test setup now makes use of the new ``begin``
  and ``end`` methods of the configurator.

Bug Fixes
---------

- When a ``repoze.bfg.exceptions.NotFound`` or
  ``repoze.bfg.exceptions.Forbidden`` *class* (as opposed to instance)
  was raised as an exception within a root factory (or route root
  factory), the exception would not be caught properly by the
  ``repoze.bfg.`` Router and it would propagate to up the call stack,
  as opposed to rendering the not found view or the forbidden view as
  would have been expected.

Get rid of hook_zca argument in configurator constructor in favor of a ``hook_zca`` method.

Provide an ``unhook_zca`` method.

  deprecated.  Its import and usage does not throw a warning, nor will
  it probably ever disappear.  However, using a
  ``repoze.bfg.configuration.Configurator`` class is now the preferred
  way to generate a WSGI application.

- The ``run.py`` module in various ``repoze.bfg`` ``paster`` templates
  now use a ``repoze.bfg.configuration.Configurator`` class instead of
  the (now-legacy) ``repoze.bfg.router.make_app`` function to produce
  a WSGI application.