Change peerinfo to a class rather than a dictionary

peer/README.md

@@ -1,3 +1,5 @@
 # PeerStore
 
 The PeerStore contains a mapping of peer IDs to PeerData objects. Each PeerData object represents a peer, and each PeerData contains a collection of protocols, addresses, and a mapping of metadata. PeerStore implements the IPeerStore (peer protocols), IAddrBook (address book), and IPeerMetadata (peer metadata) interfaces, which allows the peer store to effectively function as a dictionary for peer ID to protocol, address, and metadata. 
+
+Note: PeerInfo represents a read-only summary of a PeerData object. Only the attributes assigned in PeerInfo are readable by references to PeerInfo objects.

peer/peerinfo.py

@@ -0,0 +1,4 @@
+class PeerInfo:
+    def __init__(self, peer_id, peer_data):
+        self.peer_id = peer_id
+        self.addrs = peer_data.get_addrs()

peer/peerstore.py

@@ -1,5 +1,6 @@
 from .peerstore_interface import IPeerStore
 from .peerdata import PeerData
+from .peerinfo import PeerInfo
 
 class PeerStore(IPeerStore):
 
@@ -24,10 +25,7 @@ class PeerStore(IPeerStore):
     def peer_info(self, peer_id):
         if peer_id in self.peer_map:
             peer = self.peer_map[peer_id]
-            return {
-                "peer_id": peer_id,
-                "addrs": peer.get_addrs()
-            }
+            return PeerInfo(peer_id, peer)
         return None
 
     def get_protocols(self, peer_id):