Adding support for SOCKS plain text authentication

Adding support for SOCKS plain text authentication

This patch adds support for SOCKS plain text (username/password)
authentication as described in RFC 1929. It adds an optional third
parameter to the socks-proxy option, which is a file containing the
login credentials.

I've been using this patch for two weeks now and it does not seem to
cause any problem. The only modifications are in the SOCKS handshake
handling and the options parser.

Signed-Off-By: Pierre Bourdon <delroth@gmail.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Acked-by: David Sommerseth <dazo@users.sourceforge.net>
Signed-off-by: David Sommerseth <dazo@users.sourceforge.net>