a channel is an agent that wraps a connection and deals with incoming messages
move test-send-message to get-registry in channel ns
Revert "make connection into an agent"

This reverts commit 731e408e408982744a907039a850e0b5aaaaf7d9.
Revert "whitespace"

This reverts commit b93c1d73391eef6f84ec4ee0374ff759370ed731.
Merge branch 'channel'