Updated script for benchmarks (on 2.x and 3.x).
Inspired by the "Tools/iobench" script.

It benchmarks various quote/unquote implementations on 2.x and 3.x.

On 2.7 the fastest implementation is something like:

    def quote(s):
        if not s or not s.rstrip(safe):
            return s
        return ''.join(map(safe_get, s))


On 3.2 the fastest implementation uses list comprehension:

    def quote_from_bytes(s):
        if not s:
            return ''
        if not s.rstrip(safe):
            return s.decode()
        return ''.join([quoter(c) for c in s])


Note: the regexp implementation is slower in both cases.