Implement self-test

[emmericp]

Tests are important! And also difficult when you have hardware dependencies :(

We can implement a simple full system test by adding another example application: ixy-dump which dumps packets to a pcap file.

We can then use all three example applications together for a system test

• send packets with ixy-pktgen (and let's add a sequence number generater here)
• forward them with ixy-fwd
• dump them to a pcap with ixy-dump

Then we can just check if the generated pcap file contains packets with increasing sequence numbers. This can be run on a single server with four connected interfaces.

The important part here is that this tests the actual applications, because there is nothing worse than having examples that just don't work because no one ever tests them.