- Allow passing in a program-wide `loglevel`
- Add detailed debug logging particularly to do with channel msg processing
and connection handling
- Don't daemonize subprocesses for now as it prevents use of
sub-sub-actors (need to solve #6 first)
- Add a `Portal.close()` which just tells the remote actor to tear down
the channel (for now)
- Add a message to signal the remote `StopAsyncIteration` from an async
gen such that the client side terminates properly as well
- Make `Actor.cancel()` cancel the channel server first
- Actors *must* complete the arbiter registeration steps before moving
on with their main taks and rpc handling
- When delivering rpc responses (using the local per caller queue) use
the blocking interface (`trio.Queue.put()`) to get backpressure
- Properly detect an `partial` wrapped async generators in `_invoke`
Fix quite a few little bugs:
- async gen func detection in `_invoke()`
- always cancel channel server on main task exit
- wait for remaining channel peers after unsub from arbiter
- return result from main task(s) all the way up to `tractor.run()`
Also add a `Portal.result()` for getting the final result(s) from the
actor's main task and fix up a bunch of docs.