expression-wise from the AST module  [ticket:26]

self.include_file(<filename>, **kwargs)

[ticket:24]

template (keyword arguments only, must be declared in that page's <%page> tag.)

propigates __nonzero__ method so it evaulates to False if not present,
True otherwise.  this way you can say % if caller:\n ${caller.body()}\n% endif

pre-process the ".." tokens before checking the filesystem

comments may contain quote characters [ticket:23]

  callable or list of callables which will be applied to the template text
  before lexing.  given the text as an argument, returns the new text.
- added mako.ext.preprocessors package, contains one preprocessor so far:
  'convert_comments', which will convert single # comments to the new ##
  format

- doc adjustments, changeset adjustments, modified unicode tests to
use ## instead of # for magic encoding comment.  # will still work for now.
- unsure whether we are going with #* *# or <%doc> for multiline comments,
looking like <%doc>.

  [ticket:16]
- cleanup in unit tests

- added "default_filters" argument to Template, TemplateLookup.  applies only to expressions,
gets prepended to "expression_filter" arg from <%page>.  defaults to ["unicode"], so that
all expressions get stringified into u'' by default (this is what Mako already does).
By setting to [], expressions are passed through raw.
- added "imports" argument to Template, TemplateLookup.  so you can predefine a list of
import statements at the top of the template.  can be used in conjunction with
default_filters.

magic encoding comment

file
- added modulename_callable to TemplateLookup to allow a function to determine module filenames
(takes filename, uri arguments).  used for [ticket:14]

with a template that indicates a non-standard encoding, are expanded into backslash-escaped
glyphs before being AST parsed [ticket:11]

converted to a list [ticket:9]

this is implemented by changing the "topleveldefs" and "closuredefs" collections
from a Set to a dictionary.  a unit test was added with alternate set-ordering
as the original issue only appeared on linux to start.
- "backslash" -> "slash" in syntax doc

occurs before filtering
- removed encoding() filter - it conflicts with the fact that unicode conversion has to
occur on the value first before being sent to the filter.  recommended way for encoded
strings is to just say unicode(x, encoding='whatever')

handling for the given expression.
usage is like:  ${data | encoding('utf-8', errors='strict')}