store container_id in proxy rather than tornado

allows restarted tornado process to be able to stop containers it didn't start
use docker.kill instead of docker.stop

We don't need a clean shutdown if we are just going to remove the container.
We can switch to stop if/when we start using pause/resume instead.
Merge pull request #23 from minrk/docker-kill

use docker.kill instead of docker.stop
Merge pull request #21 from minrk/container_id_proxy

store container_id in proxy rather than tornado
Use the actual container ID
Merge pull request #24 from jupyter/container_id

Use the actual container ID
Enforce local installation
Handle static, robots
Merge pull request #25 from jupyter/launchie_dev

Enforce local installation
Merge pull request #26 from jupyter/robots

Handle static, robots
Check the status of the notebook itself
Delete old fudge factor
Merge pull request #29 from rgbkrk/reach_notebook

Check the status of the notebook itself
Clean up logging
Merge pull request #30 from rgbkrk/better_logging

Clean up logging
allow requesting specific user IDs

Visiting /user-foo/ will no longer 404 if it went down.
Instead, it will start up a new server at that URL.
extra message when requesting a specific path