Use SuperPacket in pfdecoder

[tomeichlersmith]

pfdecoder was started before SuperPacket was implemented, now that SuperPacket is here, we should use it within pfdecoder so that future changes to the decoding only need to be done in one place.

[tomeichlersmith]

I think a more long-lasting idea would be to update the decoding sub module to be a more modern C++ implementation of a decoding class. This would mean the member variables would be the already decoded values of interest. The inputs to a constructor would be a std::vector<uint32_t> and there would be a input-stream class for reading out the data from a file.