Protocol muxing (#82)

* Implement protocol muxing

* Integrate protocol muxing into new stream and listen's conn handler

* Fix bugs in protocol muxing

* Remove blank line

* Add comments and fix linting issues

* Fix order of parameters to select_one_of to match interface

* Use array of protocol ids in new stream instead of protocol id

* Add basic protocol muxer tests

* Add todo

* Modify new stream to take in protocol ids

* Add check to all tests to ensure protocol id is saved to net stream properly

* Lint tests

* Fix lint issues

* Add todo

* Modify port numbers in tests

* Fix linting issues

* Add more documentation to functions

* Add docs describing classes and fix indent error

protocol_muxer/multiselect_muxer_interface.py

@@ -0,0 +1,25 @@
+from abc import ABC, abstractmethod
+
+class IMultiselectMuxer(ABC):
+    """
+    Multiselect module that is responsible for responding to
+    a multiselect client and deciding on
+    a specific protocol and handler pair to use for communication
+    """
+
+    @abstractmethod
+    def add_handler(self, protocol, handler):
+        """
+        Store the handler with the given protocol
+        :param protocol: protocol name
+        :param handler: handler function
+        """
+
+    @abstractmethod
+    def negotiate(self, stream):
+        """
+        Negotiate performs protocol selection
+        :param stream: stream to negotiate on
+        :return: selected protocol name, handler function
+        :raise Exception: negotiation failed exception
+        """