[Twisted-Python] txsni + alpn + acme (letsencrypt)

[Daniel Holth]

HOLY REGEX BATMAN

class _ConnectionProxy(object):

    def bio_write(self, buf):
        if ACME_TLS_1 in buf:
            self.acme_tls_1 = True
        self.bio_write = self._obj.bio_write
        return self._obj.bio_write(buf)
Now we can choose the acme certificate store in the sni callback and
make letsencrypt happy!