Let's make node accept "a hashgraph" instead of "the
hashgraph".
To do so, we changed the struct Hashgraph to be instead a
BTreeHashgraph structure implementing the Hashgraph trait
and then make Node get a Rc<RefCell<Hashgraph>> instead of
just Hashgraph.
Let's make node accept "a hashgraph" instead of "the hashgraph".
To do so, we changed the struct
Hashgraphto be instead aBTreeHashgraphstructure implementing theHashgraphtrait and then makeNodeget aRc<RefCell<Hashgraph>>instead of justHashgraph.