- fixed buffering when disable_unicode is used

- some functions on Context are now private:
_push_buffer(), _pop_buffer(),
caller_stack._push_frame(), caller_stack._pop_frame().
- implemented [ticket:76] inlining of context.write()

from Mike Orr

python via _ast and google app engine

  argument passed to Template or TemplateLookup.  All
  unicode-awareness and filtering is turned off, and template
  modules are generated with the appropriate magic encoding
  comment.  In this mode, template expressions can only
  receive raw bytestrings or Unicode objects which represent
  straight ASCII, and render_unicode() may not be used.
  [ticket:77]  (courtesy anonymous guest)

  directly to the %page or %def, i.e.
  <%def name="foo(x)" cached="True" cache_key="${x}"/>
  [ticket:78]

  more elaborate combinations of quotes and comments
  [ticket:75]

  configured as module level attributes, i.e. within
  <%! %> sections [ticket:62]
- removed reliance upon KeyError/AttributeError in namespace.__getattr__

  of html_error_template() to the buffered output

  blank exception pages when an inheriting template is
  present [ticket:71]

  caching, combined with an expression-based cache_key,
  combined with the usage of <%namespace import="*"/>

fixes #69

  with identifiers like "else", "finally", etc. inside them
  [ticket:68]

  did not have access to the correct context containing
  their 'self' and 'parent'

  incorrect "self" in the current context

  within a <%call> tag's argument list propigates 'caller'
  to the %call function itself (propigates to the inner
  calls too, this is a slight side effect which previously
  existed anyway)

exception reporter [ticket:51]

newlines in CRLF templates. follow up to #16.
thanks Eric Woroshow

o update the babelplugin test for babel 0.9

fixes #48

i.e. if foo: # a comment, [ticket:53], thanks to
Paul Colomiets