Add basic support for multiaddr addresses and improvement around peer id (#75)

* Improved peer ID construction and usage

* peer id object is directly passed to the network

no need to cast from a string to an ID

* don't base64 encode the peer id when loading from public key

* use proper multiaddr address

- keep multiaddr object into peerstore instead of string
- update network code to use new multiaddr lib
- update tests and example

* don't instanciate peerstore object in constructor

This has side effect where the same peerstore
is used for different instance of Libp2p

* add connect method to basic_host

* use zaibon's fork of sbuss/py-multiaddr

* lint

libp2p/libp2p.py

@@ -1,5 +1,7 @@
 from Crypto.PublicKey import RSA
+import multiaddr
 from peer.peerstore import PeerStore
+from peer.id import id_from_public_key
 from network.swarm import Swarm
 from host.basic_host import BasicHost
 from transport.upgrader import TransportUpgrader
@@ -11,10 +13,11 @@ async def new_node(id_opt=None, transport_opt=None, \
 
     if id_opt is None:
         new_key = RSA.generate(2048, e=65537)
-        id_opt = new_key.publickey().exportKey("PEM")
+        id_opt = id_from_public_key(new_key.publickey())
         # private_key = new_key.exportKey("PEM")
 
     transport_opt = transport_opt or ["/ip4/127.0.0.1/tcp/8001"]
+    transport_opt = [multiaddr.Multiaddr(t) for t in transport_opt]
     muxer_opt = muxer_opt or ["mplex/6.7.0"]
     sec_opt = sec_opt or ["secio"]
     peerstore = peerstore or PeerStore()