l2tpclient.py RMZ 2012

Naive implementation of a LAC (L2TP client) written in python.
It implement very partially RFC2661. 
Limited to only one tunnel and one session.
Relies on pppd for ppp connectivity.
Know to work with xl2tpd and Redback LNS implementation.
Tested on Linux, and OpenBSD 
(warning MTU on OpenBSD need to be at most 850, cause of the 1024 lentgh buffer hardcoded in the tty code, or patch your kernel)