Made a small optimization to the template lexer. There's no need to calculate...

        otherwise it should be treated as a literal string.

        """

        if in_tag:

            # The [2:-2] ranges below strip off *_TAG_START and *_TAG_END.

            # We could do len(BLOCK_TAG_START) to be more "correct", but we've

            # hard-coded the 2s here for performance. And it's not like

            # the TAG_START values are going to change anytime, anyway.

            if token_string.startswith(VARIABLE_TAG_START):

                token = Token(TOKEN_VAR,

                              token_string[

                                len(VARIABLE_TAG_START):-len(VARIABLE_TAG_END)

                              ].strip())

                token = Token(TOKEN_VAR, token_string[2:-2].strip())

            elif token_string.startswith(BLOCK_TAG_START):

                token = Token(TOKEN_BLOCK,

                              token_string[

                                len(BLOCK_TAG_START):-len(BLOCK_TAG_END)

                              ].strip())

                token = Token(TOKEN_BLOCK, token_string[2:-2].strip())

            elif token_string.startswith(COMMENT_TAG_START):

                content = ''

                if token_string.find(TRANSLATOR_COMMENT_MARK):

                    content = token_string[

                                len(COMMENT_TAG_START):-len(COMMENT_TAG_END)

                              ].strip()

                    content = token_string[2:-2].strip()

                token = Token(TOKEN_COMMENT, content)

        else:

            token = Token(TOKEN_TEXT, token_string)