* Remove unused code from compat module

* Remove unused dictconfig

* Remove total_ordering compat layer

* Remove compatibility layer

This completely removes the compat module. It moves utilities
functions (`as_text` and `decode_redis_hash`) to the `utils`
module, is eliminates the use of the proxies `text_type` and
`string_types`, using the `str` construct directly.

* Remove compat module

Finishes the cleaning of the compatibility module.
The last function being the `is_python_version` function
which was being used internally.

* Fix old import

* Fix Imports

* Remove Dummy (Force GH Actions)

* Fix Imports

* Organize Imports

* Move common flake8 options into config file

Currently --max-line-length being specified in two places. Just use the
existing value in the config file as the source of truth.

Move --count and --statistics to config file as well.

* Fix some lints

There are small typos in:
- docs/docs/exceptions.md
- docs/docs/jobs.md
- rq/queue.py
- tests/fixtures.py
- tests/test_job.py

Fixes:
- Should read `slightly` rather than `slighty`.
- Should read `requeuing` rather than `requeueing`.
- Should read `implementers` rather than `implementors`.
- Should read `definition` rather than `defition`.
- Should read `canceled` rather than `canceld`.

Signed-off-by: Tim Gates <tim.gates@iress.com>

* Drop syntax required only for Python 2

* Drop python2-style super() calls

Co-authored-by: Selwin Ong <selwin.ong@gmail.com>

* Support enqueueing with on_success_callback

* Got success callback to execute properly

* Added on_failure callback

* Document success and failure callbacks

* More Flake8 fixes

* Mention that options can also be passed in via environment variables

* Increase coverage on test_callbacks.py

* Removed deprecated (object) inheritance
Add new py38,py39 versions to tox, removed deprecated py27,py34
Replace enum internal function with Enum class

* fix

* add asyncio runner

* add asyncio runner

* fix for old version

* fix tests

* Also accept lists and tuples as value of `depends_on`.

* The elements of the lists/tuples may be either Jobs or Job IDs.
* A single Job / Job ID is still accepted as well.

* Represent _all_ job dependencies in `Job.to_dict()`.

We now represent the entire list, instead of just the first element.

* Fix some doctext regarding plurality of dependencies.

* Add unit tests for job dependencies.

* One unit test establishes a pattern for checking execution order as affected by dependencies.

* Another unit test applies this pattern to the new capability to name multiple dependencies.

* Add unit test for new `depends_on` input formats.

Also test that these are properly persisted.

* Repair `Job.restore()`.

Need to convert bytes back to strings when reloading `dependency_ids`.

* Maintain backwards compat. in `Job.to_dict()`.

Keep the old `dependency_id` (singular) key.

* Provide coverage for new test fixture.

* Simplify some code.

Cut some superfluous `as_text()` calls left over from an earlier commit.

* Check for `dependency_id` in `Job.restore()` for backwd. compat.

Also eliminate use of `as_text()` here, in favor of `.decode()`.

* Switch to snake case instead of camel case.

* Eliminate some usages of `as_text()`.

Also cut some `print` statements.

* Cleanup.

* Accept arbitrary iterables for `Job`'s `depends_on` kwarg.

Instead of requiring a list or tuple, we now make use of `ensure_list()`.

* Add test fixtures.

* Provide a system to get two workers working simultaneously, using `multiprocessing`.
* Define a simple job that just says whether its dependencies are met.
* In `rpush`, make an option to record the name of the worker.

* Improve unit tests on execution order with dependencies.

These now actually have two workers going, which makes a more thorough test.

* Add unit test examining `Job.dependencies_are_met()` at execution time.

* Redesign dependency execution order unit tests.

* Simplify assertions.

* Improve doctext and formatting.

* Move fixture tests to new, dedicated module `test_fixtures.py`.

* Use `enqueue` instead of `enqueue_call` in new unit tests.

* Added job.worker_name

* Fix compatibility with Redis server 3.x

* Document job.worker_name

* Removed some Python 2 compatibility stuff.

* Remove unused codes