Remove unused code.
Reduce test logging levels.
Test cleanup.
Test improvements.
Code improvements.
Move specs into appropriate subdirectories.
Namespace specs appropriately.
Fix tests where we couldn't run binary after running in-memory.

We never uninstalled our signal handlers, so running rflow from Open3 always triggered SIGCHLD, which triggered a shutdown.
Caller should be logging exceptions, instead of logging at the callsite.
Refactor rflow.rb.
Refactor rflow/master.rb and create DaemonProcess.
Refactor rflow/shard.rb and create ChildProcess.
Refactor rflow/component.rb.
Refactor rflow/components/raw.rb.
Refactor rflow/component/port.rb.
Refactor rflow/connection.rb.
Refactor rflow/connections/zmq_connection.rb.
Refactor rflow/logger.rb.
Refactor rflow/message.rb.
Refactor rflow/pid_file.rb.