Add a benchmark script.

Add a benchmark script.

This script sets up two network namespaces connected via a veth tunnel with
the netem qdisc to simulate "realistic" network conditions.

It first uses socat to transmit data via regular TCP, then transmits the
same amount of data using the UTCP test program. It prints the time it took
for both methods, and stores a packet trace for both methods so it can be
analyzed.