Stream rearchitecture (#126)

* Add generic protocol handler

* Add generic protocol handler to stream muxing pipeline

* Modify conn_handler to only deal with connections

* mplex accept stream architecture changes

* Add create generic protocol handler

* Fix minor bugs

* who would win 4 devs or one not

* Debugging

* rearch with handle_incoming infinite loop, seems to work, needs cleanup"

* passing linting, still needs cleanup

* fixing linting again; code still needs cleanup

* fixing tests; code still needs cleanup

* adding test cleanup and task cleanup, removing prints

* linting, and cleanup complete

* storing connections based on peer id

* remove dead code

* remove unnecessary peer_id

tests/protocol_muxer/test_protocol_muxer.py

@@ -1,5 +1,6 @@
 import pytest
 
+from tests.utils import cleanup
 from libp2p import new_node
 from libp2p.protocol_muxer.multiselect_client import MultiselectClientError
 
@@ -49,7 +50,7 @@ async def perform_simple_test(expected_selected_protocol,
     assert expected_selected_protocol == stream.get_protocol()
 
     # Success, terminate pending tasks.
-    return
+    await cleanup()
 
 
 @pytest.mark.asyncio
@@ -65,6 +66,9 @@ async def test_single_protocol_fails():
         await perform_simple_test("", ["/echo/1.0.0"],
                                   ["/potato/1.0.0"])
 
+    # Cleanup not reached on error
+    await cleanup()
+
 
 @pytest.mark.asyncio
 async def test_multiple_protocol_first_is_valid_succeeds():
@@ -91,3 +95,6 @@ async def test_multiple_protocol_fails():
     with pytest.raises(MultiselectClientError):
         await perform_simple_test("", protocols_for_client,
                                   protocols_for_listener)
+
+    # Cleanup not reached on error
+    await cleanup()