- added "bytestring passthru" mode, via `disable_unicode=True`
  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)