Cleaned up system configuration files -- removed few obsolete parameters,
documented the remaining ones (sysdep/cf/README). Available configurations: o linux-20: Old Linux interface via /proc/net/route (selected by default on pre-2.1 kernels). o linux-21: Old Linux interface, but device routes handled by the kernel (selected by default for 2.1 and newer kernels). o linux-22: Linux with Netlink (I play with it a lot yet, so it isn't a default). o linux-ipv6: Prototype config for IPv6 on Linux. Not functional yet.