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

tests/peer/test_peerid.py

@@ -0,0 +1,9 @@
+from Crypto.PublicKey import RSA
+from peer.id import id_from_private_key, id_from_public_key
+
+
+def test_id_from_private_key():
+    key = RSA.generate(2048, e=65537)
+    id_from_pub = id_from_public_key(key.publickey())
+    id_from_priv = id_from_private_key(key)
+    assert id_from_pub == id_from_priv

tests/peer/test_peerinfo.py

@@ -0,0 +1,11 @@
+import multiaddr
+from peer.peerinfo import info_from_p2p_addr
+
+
+def test_info_from_p2p_addr():
+    # pylint: disable=line-too-long
+    m_addr = multiaddr.Multiaddr('/ip4/127.0.0.1/tcp/8000/ipfs/3YgLAeMKSAPcGqZkAt8mREqhQXmJT8SN8VCMN4T6ih4GNX9wvK8mWJnWZ1qA2mLdCQ')
+    info = info_from_p2p_addr(m_addr)
+    assert info.peer_id.pretty() == '3YgLAeMKSAPcGqZkAt8mREqhQXmJT8SN8VCMN4T6ih4GNX9wvK8mWJnWZ1qA2mLdCQ'
+    assert len(info.addrs) == 1
+    assert str(info.addrs[0]) == '/ip4/127.0.0.1/tcp/8000'