* 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
* Cleanup fulfilled requests after approve
* Modified tests
* Moved to separate test, add user to access functions
* Moved to separate test and added test cases
* Fixed issue with dryrun
* More changes based on comments
* 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