Huey

* Added support for gracefully restarting the consumer using SIGHUP.
* Fixed a bug where periodic tasks were not being given unique task IDs when
executed by the consumer. Periodic tasks now receive a unique ID each time
they are invoked.

[View commits](https://github.com/coleifer/huey/compare/1.5.1...1.5.2)

Added support for specifying a `retry` and `retry_delay` on periodic tasks.
Simply pass the desired values into the `periodic_task()` decorator after the
validation function, as keyword arguments.

[View commits](https://github.com/coleifer/huey/compare/1.5.0...1.5.1)

* Allow all instances of a task to be revoked/restored by adding the
`revoke()`, `restore()` and `is_revoked()` methods to all decorated tasks
(where previously they were only available on periodic tasks).
* Periodic task instances now have a unique identifier.
* Added documentation on how to correctly use the Django consumer management
command with the `gevent` worker model.
* Logging will lazily resolve log messages.
* Bug was fixed that prevented the local (non-global) task registry from
working as intended. This is now fixed.
* Docstrings added to the `BaseStorage` APIs.

Thanks to mindojo-victor and nachtmaar for help with some of the above items.

[View commits](https://github.com/coleifer/huey/compare/1.4.1...1.5.0)

* Support using `7` to represent *Sunday* when doing day-of-week calculations
in the `crontab` helper.
* Fix bug 243, wherein Django interpreted boolean CLI arguments as having a
boolean default value.

[View commits](https://github.com/coleifer/huey/compare/1.4.0...1.4.1)

Fixed a subtle bug in the way Huey calculated when to run the periodic task
scheduler. If you had configured the consumer to check the schedule at an
interval that was not a factor of 60, then there is a chance that periodic
tasks may be scheduled at incorrect intervals from one minute to the next. This
is fixed in 1.4.0.

Added better signal handling in order to support graceful shutdown. Graceful
shutdown involves letting workers finish executing any tasks they may be
processing at the time the shutdown signal is received. The default behavior is
to interrupt the workers mid-task. Huey uses `SIGTERM` to shutdown the
consumer immediately, and `SIGINT` to gracefully shutdown.

Added support for using either a global task registry, or a registry bound to
a particular `Huey` instance. The default behavior is to use a global registry
(backwards-compatible). To bind the registry to a single `Huey` instance, pass
`global_registry=False` when initializing your `Huey` object.

Added a `reschedule()` method to the `TaskResultWrapper`.

Documentation clean-ups and additions, particularly around the logic used to
handle datetime conversion. Also added docs on shutdown modes for huey
consumer.

[View commits](https://github.com/coleifer/huey/compare/1.3.1...1.4.0)

Smarter conversion between datetimes, so that huey will correctly interpret
naive or timezone-aware datetimes and properly convert to UTC when configured
to do so. Previously, huey only operated on naive datetimes. Many thanks to
Antoine for this patch-set.

Documentation clean-ups and additions.

[View commits](https://github.com/coleifer/huey/compare/1.3.0...1.3.1)