Req: Support multiple serial ports simultaneously

[pklapperich]

It would be super handy to use the RX lines from 2 different UARTs to spy on the entire communication between 2 devices with have both sides of the conversation in the same PCAP file.

[j123b567]

Some notes:

Implementing #3 will solve this from wireshark point of view. From wireshark, it is possible to listen on multiple interfaces. I must investigate if it is also possible from tshark.

If you need standalone application, it is still possible to use mergecap later on two separate pcaps.