Initial winsock support patch from nu774.

Some tweak might be still needed to take care of OPENSSL_AppLink
to get https support working. In win32, user application of openssl
is required to include openssl/applink.c or something, when openssl
is compiled with OPENSSL_USE_APPLINK.

I don't know how it should be taken care of, from the library point of
view (it must be done by user of libopusfile, since openssl always
searches that function in executable module).

Posted to the hydrogenaudio format 2012 November 19.
http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=97856&view=findpost&p=814582