dynamic node discovery

[maxtheaxe]

• currently checks hard-coded IP address for node (and assumes valid, does not verify)
• needs to search for (and check) node instead:
• should probably collect other mac addresses on network and identify rpi prefix (as a holdover until better method selected)
• use arp packets(?) or basic custom handshake to verify rpi is pollen node
• if not, check other rpis
• could also spoof mac address on node end to identify self as pollen node, rather than checking all rpi