Profinet DCP sketch implementation

[Łukasz Dywicki <lu...@code-house.org>]

Hi to everyone,
I wanted to let you know that I made some progress on java version of
Profinet DCP driver. My main interest working on that was really
discovery of the devices. I've implemented only frames around that.

As a part of work I also adjusted pcap4j transport, so it sends ethernet
frames back to the link, so it is possible to make a live test with real
devices. It is quite simple.

Sources are available here:
https://github.com/apache/plc4x/commits/feature/profinet

If you would like to run it, start point is a main() method in:
org.apache.plc4x.java.profinet.dcp.ProfinetDCPPlcDriver

I've embedded my network card mac address there, so you need to adjust it.

Cheers,
Łukasz