Update to 0.19:

0.19 (2013-04-19)
=================

Features added
--------------

* New directives ``c_string_type`` and ``c_string_encoding`` to more easily
  and automatically convert between C strings and the different Python string
  types.

* The extension type flag ``Py_TPFLAGS_HAVE_VERSION_TAG`` is enabled by default
  on extension types and can be disabled using the ``type_version_tag`` compiler
  directive.

* EXPERIMENTAL support for simple Cython code level line tracing.  Enabled by
  the "linetrace" compiler directive.

* Cython implemented functions make their argument and return type annotations
  available through the ``__annotations__`` attribute (PEP 3107).

* Access to non-cdef module globals and Python object attributes is faster.

* ``Py_UNICODE*`` coerces from and to Python unicode strings.  This is
  helpful when talking to Windows APIs, which use compatible wchar_t
  arrays for strings.  Note that the ``Py_UNICODE`` type is otherwise
  deprecated as of CPython 3.3.

* ``isinstance(obj, basestring)`` is optimised.  In Python 3 it only tests
  for instances of ``str`` (i.e. Py2 ``unicode``).

* The ``basestring`` builtin is mapped to ``str`` (i.e. Py2 ``unicode``) when
  compiling the generated C code under Python 3.

* Closures use freelists, which can speed up their creation quite substantially.
  This is also visible for short running generator expressions, for example.

* A new class decorator ``@cython.freelist(N)`` creates a static freelist of N
  instances for an extension type, thus avoiding the costly allocation step if
  possible. This can speed up object instantiation by 20-30% in suitable
  scenarios. Note that freelists are currently only supported for base types,
  not for types that inherit from others.

* Fast extension type instantiation using the ``Type.__new__(Type)`` idiom has
  gained support for passing arguments.  It is also a bit faster for types defined
  inside of the module.

* The Python2-only dict methods ``.iter*()`` and ``.view*()`` (requires Python 2.7)
  are automatically mapped to the equivalent keys/values/items methods in Python 3
  for typed dictionaries.

* 2-value slicing of unknown objects passes the correct slice when the ``getitem``
  protocol is used instead of the ``getslice`` protocol (especially in Python 3),
  i.e. ``None`` values for missing bounds instead of ``[0,maxsize]``.  It is also
  a bit faster in some cases, e.g. for constant bounds.  This fixes trac ticket 636.

* Slicing unicode strings, lists and tuples is faster.

* list.append() is faster on average.

* ``raise Exception() from None`` suppresses the exception context in Py3.3.

* Py3 compatible ``exec(tuple)`` syntax is supported in Py2 code.

* Keyword arguments are supported for cdef functions.

* External C++ classes can be declared nogil.  Patch by John Stumpo.  This fixes
  trac ticket 805.

Bugs fixed
----------

* Cascaded assignments of None values to extension type variables failed with
  a ``TypeError`` at runtime.

* The ``__defaults__`` attribute was not writable for Cython implemented
  functions.

* Default values of keyword-only arguments showed up in ``__defaults__`` instead
  of ``__kwdefaults__`` (which was not implemented).  Both are available for
  Cython implemented functions now, as specified in Python 3.x.

* ``yield`` works inside of ``with gil`` sections.  It previously lead to a crash.
  This fixes trac ticket 803.

* Static methods without explicitly named positional arguments (e.g. having only
  ``*args``) crashed when being called.  This fixes trac ticket 804.

* ``dir()`` without arguments previously returned an unsorted list, which now
  gets sorted as expected.

* ``dict.items()``, ``dict.keys()`` and ``dict.values()`` no longer return lists
  in Python 3.

* Exiting from an ``except-as`` clause now deletes the exception in Python 3 mode.

* The declarations of ``frexp()`` and ``ldexp()`` in ``math.pxd`` were incorrect.

(wiz)