replace get_hub().switch() with self.parent.switch - should be faster as it avoids accessing threadlocal

--HG--
extra : transplant_source : %95%EA%B0%28b%28%EB%3E%EC%B5%DC%26%AD%86%CA%89/%C6%B6%85

--HG--
extra : transplant_source : %7B%FDs%CF%3D0%CD%0C%25%C8%FA-F%E5%AFV%97%3D%8C%B2

--HG--
extra : transplant_source : %F7c8%40%E6%E5m%C4%25%8F%29%A8E%82%DF%B6c%F5%9A%A7

--HG--
extra : transplant_source : %D03%AC%98%5E%E6%E2T%06%82H%D8%7F%FD%E2%9C%A36%DDb

socket: resolve ipv6 and ipv4 concurrently in getaddrinfo() thus reducing the delay in AF_UNSPEC case

test__socket_dns.py: do not raise an error when getaddrinfo raises DNSError(66, 'unknown') instead of gaierror(-5, 'No address associated with hostname')

Fix for issue #56: Make socket.getaddrinfo handle AF_UNSPEC properly and resolve service names. Thanks to Elizabeth Jennifer Myers.

testrunner.py: convert path to testresults.sqlite3 to work with tests that chdir (test__doctests.py)

--HG--
extra : transplant_source : i%9B%F8%D0%AB.%9F%02%9A%A4%2C%B1M%0C%B0%CC%03%12.%E2

--HG--
extra : transplant_source : I8%8F%CF%9C%8D%84%B1%D9%29%A4E%8C%3DHf%DD%F6%9E%E8