* Allows SecureStreamSocket::attach to be used in server connections

* Allows SecureStreamSocket::attach to be used in server connections
* Move order of condition for isLocalHost in peer certificate verification, to skip DNS lookup if not needed

fixes #539

I created a SSL client and server in Poco, and tested them with a Go client and server, and between them. The communication was successful in all cases.

I also changed the condition order for "isLocalHost", because it makes a DNS lookup, even when not needed.