Luigi

* revert tornado upgrade (2504)
Upgrading tornado unfortunately breaks older version of Python

Added
luigi:
- Add Data Revenue to the `blogged` list (2472)
- Add default reviewers in CODEOWNERS (2465)
- Optional TOML configs support (2457)
- Add support for multiple requires and inherits arguments (2475)
- Add a visiblity level for luigi.Parameters (2278)
- Make logging of RPC retries configurable 2486
- Added a new event 'progress' (2498)
luigi.contrib:
- Additions to provide support for the Load Sharing Facility (LSF) job scheduler (2373)
- Added default port behaviour for Redshift (2474)
- Add metadata columns to the RDBMS contrib (2440)
- Use passed password when create a redis connection (2489)

Changed
luigi:
- Update supplementary github files to improve repo organization and maintenance (2463)
- Use task_id in Task.__eq__ comparison (2462)
- Replace luigi.Task by RunOnceTask in scheduler_visualisation_test (2476)
- (Breaking change) Bump tornado milestone version (2490)
This changes requires Python version 2.7.9+ and 3.4+
luigi.contrib:
- S3 client refactor (2482)
- Update moto to 1.x milestone version (2471)

Fixed
luigi:
- Fix Scheduler.add_task to overwrite accepts_messages attribute. (2469)
- Fix race condition (2477)
- Fix attribute forwarding for tasks with dynamic dependencies (2478)
luigi.contrib:
- Fix transfer config import (2458)

Removed
luigi:
- Remove long-deprecated scheduler config variable alternatives (2491)

Added
luigi:
- Add a configuration parameter to force multiprocessing (2401)
- Add a configuration parameter to enable/disable the pause button (2399)
- Send messages from scheduler to tasks (via "Send message" UI button) (2426)
- Allow to inject a context manager around `TaskProcess.run` (via `task_process_context` configuration parameter) (2449)
luigi.contrib:
- S3: use Boto3 for the `S3Client` (2423, 2149)
- GCS: add method to push files using multiprocessing (2376)
- HDFS: add `get_merge` to snakebite client (2410)
- Redshift: add schema to DB if it doesn't exist (2439)
- Redshift: add table constraints support (2435)

Fixed
luigi:
- Allow long parameters in task history DB SQL result store (2404)
- Fix `MissingParameterException` when generating execution summary (2415)
- Fix luigid crash due to configuration file parsing (2394)
- Allow explicit parsing of `BoolParameters` (via `luigi.BoolParameter.parsing` variable) (2427)
- Make `ChoiceParameter` check if option is valid within `.normalize` (2454)
- ...and a good deal of documentation fixes and similar.
luigi.contrib:
- BigQuery: fix `bulk_complete` failing when argument is a generator (2441)
- Kubernetes: prevent `KeyError` in `KubernetesJobTask` (2433)
- Kubernetes: don't set `activeDeadlineSeconds` by default (2452)

Fixed
luigi
- append is vulnerable of xss 2391

Added
luigi:
- Add google-auth-httplib2 as dependency (2384)
- Add new company user (2388)
- Allow release of resources during task running. (2346)
luigi.contrib:
- Add parameterized backoff limit (2375)

Fixed
luigi:
- Typo in running luigi documentation (2387)
- Skip running coverage on unreasonable files
- Pass kwargs to `discovery.build()` when instantiating `GSCClient`. (2291)
- Removed message 'No Instance(s) Available.' in Windows when starting … 2294

Added
luigi:
- Added generated data files to `.gitignore` (2367)
luigi.contrib:
- Add possibility to specify `Redshift` column compression (2343)

Changed
luigi:
- Show status message button in worker tab when only progress is set (2344)
- Verbose worker error logging (2353)
luigi.contrib:
- Replace `oauth2client` by `google-auth` (2361)

Fixed
luigi:
- Fix unicode formatting (2339)
luigi.contrib:
- Fix `contrib.docker_runner` exit code check (2356)