* upgrade celery to 4.0.2
* using Redis for unit tests (sqla broker not supported in Celery 4)
* Setting Celery's soft_time_limit based on `SQLLAB_ASYNC_TIME_LIMIT_SEC` config
* Better error handling in async tasks
* Better statsd logging in async tasks
* show [pending/running] query status in Results tab
* systematically using sqla NullPool on worker (async) to limit number
of database connections
* remove network status feature
* only fetch queries if there are started or running queries
* don't use local storage
* remove last network status from actions
* don't remove support for local storage
* address pr comments and linting
* use .some rather than .forEach
* Fixed js error when results are not available
* Flush data and query in results when running new query, keeping columns
* add exception for columns
* Move setState from componentWillMount to componentWillReceiveProps
* Nit
* Change in files
* Renamin files and folders
* cleaning up a single piece of lint
* Removing boat picture from docs
* add superset word mark
* Update rename note in docs
* Fixing images
* Pinning datatables
* Fixing issues with mapbox-gl
* Forgot to rename one file
* Linting
* v0.13.0
* adding pyyaml to dev-reqs
