from tuple to frozenset, as this is expected to be
  a set by default.  [ticket:208]

  TemplateLookup, allows alternate Lexer classes
  to be used.

- dont need 2to3
- clean up some list() calls we dont need

having some weird unicode issues I can't debug; the meaning of
str.encode() seems to be changing globally somehow

Provide a list of names to import from __future__ to Template or
TemplateLookup, and it will render the import from __future__
statement at the top of the generated code so that it actually works.

  <%text> tag so that it pulls locally specified
  identifiers from the context the same
  way as that of <%block> and <%filter>.

  now succeed, as "pass" is added for these
  when no statements are otherwise present.
  Courtesy Ben Trofatter [ticket:146]

- fix up links, formatting in docs
- remove some repetition in the _compile logic

  "pass_context"; when True, the keyword argument
  'context' will be passed to get_or_create()
  containing the Mako Context object.
  [ticket:185]

- changelog

  nesting multiple def-calls with content.
  Thanks to Jeff Dairiki. [ticket:186]

  within extra arguments to <%block>, <%def>, i.e.
  <%block name="foo" cache_key="${somekey}">.
  Filters can also be used in this way, i.e.
  <%def name="foo()" filter="myfilter">
  then template.render(myfilter=some_callable)
  [ticket:180]

  system, whereby the usage of Beaker is just the
  default plugin.   Template and TemplateLookup
  now accept a string "cache_impl" parameter which
  refers to the name of a cache plugin, defaulting
  to the name 'beaker'.  New plugins can be
  registered as pkg_resources entrypoints under
  the group "mako.cache", or registered directly
  using mako.cache.register_plugin().  The
  core plugin is the mako.cache.CacheImpl
  class.

- The <%def>, <%block> and <%page> tags now accept
  any argument named "cache_*", and the key
  minus the "cache_" prefix will be passed as keyword
  arguments to the CacheImpl methods.

- Template and TemplateLookup now accept an argument
  cache_args, which refers to a dictionary containing
  cache parameters.  The cache_dir, cache_url, cache_type,
  cache_timeout arguments are deprecated (will probably
  never be removed, however) and can be passed
  now as cache_args={'url':<some url>, 'type':'memcached',
  'timeout':50, 'dir':'/path/to/some/directory'}

  whereby the identity of the "caller" callable
  inside the <%def> would be corrupted by the
  presence of another <%call> in the same block.
  [ticket:170]

  evaluates its contents in-place.
  Can be named or anonymous,
  the named version is intended for inheritance
  layouts where any given section can be
  surrounded by the <%block> tag in order for
  it to become overrideable by inheriting
  templates, without the need to specify a
  top-level <%def> plus explicit call.
  Modified scoping and argument rules as well as a
  more strictly enforced usage scheme make it ideal
  for this purpose without at all replacing most
  other things that defs are still good for.
  Lots of new docs. [ticket:164]

- convert heading copyrights to 2006-2011, reference AUTHORS file

  strict_undefined=True, will cause
  variables not found in the context to
  raise a NameError immediately, instead of
  defaulting to the UNDEFINED value.

  i.e. in place of cgi.escape().  Faster
  C-based implementation and also escapes
  single quotes for additional security.
  Supports the __html__ attribute for
  the given expression as well.

  When using "disable_unicode" mode,
  a pure Python HTML escaper function
  is used which also quotes single quotes.

  Note that Pylons by default doesn't
  use Mako's filter - check your
  environment.py file.

  uncommon feature, have been improved.  The defs
  no longer get doubly-rendered in the body() scope,
  and now allow local variable assignment without
  breakage.  [ticket:109]

  % if: %endif, etc. [ticket:94]
- finished cleanup for codegen.py, [ticket:98]

- Python 3 support is added ! See README.py3k
  for installation and testing notes.
  [ticket:119]

- Source code escaping has been simplified.
  In particular, module source files are now
  generated with the Python "magic encoding
  comment", and source code is passed through
  mostly unescaped, except for that code which
  is regenerated from parsed Python source.
  This fixes usage of unicode in
  <%namespace:defname> tags.  [ticket:99]

- start work on #98

  allows custom decoration functions to wrap
  rendering callables.  Mainly intended for
  custom caching algorithms, not sure what
  other uses there may be (but there may be).
  Examples are in the "filtering" docs.

  http://techspot.zzzeek.org/?p=28 has now
  been added as a built in syntax, and is recommended
  as a more modern syntax versus <%call expr="expression">.
  The %call tag itself will always remain,
  with <%namespacename:defname> presenting a more HTML-like
  alternative to calling defs, both plain and
  nested.  Many examples of the new syntax are in the
  "Calling a def with embedded content" section
  of the docs.

cache sends in a "defname" parameter so that the cache can map settings to that name, instead of the key.
eliminates the need to store all Value objects which will use up RAM in a dynamic-key scenario.

an expired section, instead of the original context
passed in [ticket:87]

a cached block would raise an error when called within a
cache-refresh operation that was initiated after the
initiating template had completed rendering.