implement @exclude functionality
implement @exclude functionality

- do not add ConnectTo lines for excluded peers
- do not set routes for networks belonging to excluded peers

but we still write the hosts/* file for these peers, so we can
still receive traffic from them through this vpn. if we would not
do this we would get lots of connection errors on both sides if
only one side excludes the other.

ryd/chaosvpn,ryd/chaosvpn,ryd/chaosvpn