Fae needs networking

Complementary to but separately from the lack of a blockchain, Fae needs a peer-to-peer (or other) networking protocol. The general nature of such a protocol for a blockchain is that it must have instructions for exchanging blocks as well as transactions not in any block; however, due to Fae's laziness, it should be expected that clients will attempt to limit their storage requirements by discarding unwanted transaction source code. So for us, the protocol also needs to fetch isolated individual transaction message bodies. Finally, various resource limits on transactions are appropriate: file size limits for each source file and message header size should both be limited (configurably).