Removed useless tests, will need to complete a more comprehensive test
suite however this is not the priority right now
Added a live value dict in the core whose values are populated by the
core's input thread
Implemented handshake in json server and handoff to endpoint
Endpoint handles connector handshake accept/decline then launches both
its IO threads alongside its heartbeat thread which contains simple
timeout logic, timeout calls connection handles to close, subsequently
killing the endpoint
Isolated the JsonServer to server.py inside protocols/json
Added specific errors for server startup timeout and server startup
failed
Refactored errors for Core to CoreError generic and refactored
StateError to CoreStateMismatchError derived from CoreError
h3cx