-  negotiate_socks_connection(+DesiredEndpoint, +StreamPair) is det
 - Negotiate a connection to DesiredEndpoint over StreamPair.
DesiredEndpoint should be in the form of either:
- hostname : port
 
ip(A,B,C,D) : port 
- Errors
 - - 
socks_error(Details) if the SOCKS negotiation failed.