Celery

* Models are run in Celery. We now poll for model logs, available as soon each model is completed. This is the most basic status update.
* Chart and map configs edited as forms.
* Basic ability to add new model config clicking 'Create New'
* Errors encountered while running models are logged to the console and growled.

Note: After the latest bayarea_urbansim commit, `nrh_estimate` and other models are throwing `Key_error: 'coefficients'`.

There is a lot of code which will surely be removed later.