Merge pull request #52 from brocaar/improve_docs

Improve docs
Add WorkerPool model.
Add worker_pools to Project model.
Link JobTemplate to Project and Job to WorkerPool.
Migrate data structure.
Delete old columns.
Fix old field references in admin / models.
Update migration deleting old columns. Update get_notification_addresses methods.
Update fixtures.
Update model tests.
Update manager tests.
Re-add PermissionAdminMixin to Job and JobTemplate.
Update resources.
Add worker-pool resource.
Update resource relations.
Add worker field to Run model.
Update tastypie to 0.9.12 stable version and fix authorization.
Update broadcast_queue.
Move sphinx requirement to dev-requirements.txt
More tests :)