Refactor notification publishing

We want to use the same code for the cli and service to
send notifications, so refactor it in a way that makes
that easier.

Change-Id: Ibffb008d03971fa88702a593eda7f7e1443d4986
Stub in the command line app

Create a new console script 'rug-ctl' based on cliff,
without anyh plugins, yet.

Change-Id: Ib3e04848ece2b4f9d192cfe39bcc9399aee94ccf
Convert the existing debug handler to messages

Replace the USR1 signal handler with a message-based
trigger instead.

Change-Id: I0a5a0be30baaf25a3edb0de9f08557b62ff5f869
implement router debug/manage commands

Refactor the command handling in the worker process to make
adding new ones easier.

Add a set of constants with the command names to avoid typos.

Implement the command for debugging a router, replacing the
old configuration-file-based system.

Remove the configuration option for specifying the directory where debug
ids were kept before.

Implement a command to restore management of a router.

Change-Id: I5dacf642cd65dc9829b165621dc99c6ed71bfee0
add tenant debug/manage commands

Change-Id: I2f625b65d4cda9b57d418741ade5d6f2ada626bb
Add comments about commands

Try to provide more detail about the commands without
going too far into creating factories and classes
to represent them, yet.

Change-Id: I58359dea069fea57b0106f1d46ff77522b4a8405
Merge pull request #94 from dhellmann/feature/cli

Add command line control interface