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

network/network_interface.py

@@ -9,6 +9,16 @@ class INetwork(ABC):
         :return: the peer id
         """
 
+    @abstractmethod
+    def dial_peer(self, peer_id):
+        """
+        dial_peer try to create a connection to peer_id
+
+        :param peer_id: peer if we want to dial
+        :raises SwarmException: raised when no address if found for peer_id
+        :return: muxed connection
+        """
+
     @abstractmethod
     def set_stream_handler(self, protocol_id, stream_handler):
         """