Remove daemons

This is to better support features like "hot restarting" and to
provide more options. Daemons locked us in on how it daemonized
processes. In particular, it caused problems with using
`Kernel.exec` to replace the current process with a new command.
This adds a simpler daemonization process and removes the
dependency.
Updated to the latest DatTCP with adjusted API

This updates DatTCP to use it's API that adds more control over
the server. This is to setup allowing building servers from file
descriptors and also "pausing" them. This modifies the interface
for servers and slightly changed the way the manager runs the
server. "Restarting" is currently disabled. This will be
reimplemented as a "hot restart".
Cleanups and re-organizations with the recent changes

* Moved `Manager` into the `CLI`. These go together; the `CLI`
  drives the `Manager` and is just a light-wrapper to it.
* `Manager` now chooses ENV vars over passed options, which are
  chosen over the host's configuration.
* Removed some no-longer needed logic from `HostData`. This logic
  has been handled elsewhere. Closes #50.
Updated benchmarks