Group, without inherent ordering, a set of keys a certain distance away from
a local key, using XOR as the distance metric
Refactored from net.i2p.router.networkdb.kademlia
In memory storage of buckets sorted by the XOR metric from the local router's
identity, with bucket N containing routers BASE^N through BASE^N+1 away, up through
2^256 bits away (since we use SHA256).