Ignore `.pyc` files in `fab check`
Celery tasks take IDs instead of objects

Changes to `tasks.py`:
* In all tasks, pass `import_type, import_event_id` instead of `ie`
* Change function order to top-down
* Add helpers to retrieve import event from type and ID

Also:
* Change task-creation calls to use the new signatures
* Remove unused `views.process_commit`
Merge pull request #1782 from RickMohr/celery-tasks-take-ids-not-objects

Celery tasks now take ID's, not objects