Dockerfile can now be used to run the daemon

Resolves #20 by making the entrypoint of the container `bash`, allowing you to specify arbitrary commands after that. For testing, this can be:

`docker -v /home/core/ircdd:/data -t ircdd-test bash -c "python setup.py flake8 && python setup.py nosetests && python setup.py install"

But you can still runn a daemonized thing by doing:

`docker -v /home/core/ircdd:/data -t ircdd-test ircdd --listen 127.0.0.1:3323

@MHarrison72