Botoflow

**Improvements**

* Add support for setting task priorities. Thanks paulcollinsiii for PR. 9

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**API Changes**

* Remove ``botoflow.retry`` module in favor of ``retry_activity``
decorator which is much more extensible and is based on ``retrying``
library.
* ``WorkflowStarter`` is now ``workflow_starter`` as context managers
should be snake case and it's better to do this now, before 1.0
release.
* Renamed ``botoflow.workflow_types`` module to ``botoflow.flow_types`` package.
* Removed ``botoflow.types`` alias. Use ``botoflow.flow_types``.
* ``async`` is now ``coroutine`` to closer align with ``asyncio`` naming. See 1 for details.

**Bugfixes**

* Fix a **critical** bug in decider history event ordering, which could affect
any workflows that execute activities/child workflows concurrently.
* ``activities`` decorator was ignoring ``data_converter`` option. Thanks glharding.
* Better wrapping of errors from SWF. Thanks glharding.

**Miscellaneous**

* It's open sourced!
* ``doc`` directory renamed to ``docs``.
* Various package naming fixes.
* Add ``CONTRIBUTING.rst``.
* Add ``README.rst``.
* Lots of work and refactoring in documentation.
* Up to date `requirements.txt`.
* CircleCI integration.
* Thanks to `Gintare Laniauskaite <http://github.com/myselfher>`_ for
work on the LOGO and documentation design!
* Add tox support and test CPython 2.7, 3.4 and 3.5.
* Mark some tests in test_async_traceback as xfail for Python 3.5.0
specifically (works fine on 3.5.1).
* Add ``botoflow.__version__``.
* ``examples`` directory and ``helloworld`` example. Thanks to l2ol33rt for contribution.

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**Improvements**

* Add ThrottlingException.
* Do not skip registration for all activities.
* Only try registering unregistered activities.
* Supporting more BaseFuture methods properly.
* *json_data_converter* - add support for Decimal objects + tests.
* *json_data_converter* - Make ActivityType serializable in cases
where ``ActivityFailedException`` is passsed throug SWF.
* *json_data_converter* - Support ``datetime`` and ``timedelta``
object serialization.
* Add support for activity retrying using the ``retrying`` library as
the base with the **major difference** being that it takes seconds
as the smallest resolution as opposed to millis.
* Support handling basic inputs that for example come from on botoflow
based workflow starters. See commit `70423b5`_ for details.

**Bugfixes**

* Fix a regression in ChildWorkflowExecutionHandler where child
workflow exceptions aren't passed to the parent process.
* Make sure that (Any|All)Future s behave wen passed in an empty
iterable (they will immediately set an empty result).
* Handle starting a child workflow with a duplicate Workflow ID.

**Miscellaneous**

* Unit and integration test improvements.
* *json_data_converter* - Unit test improvements.

----------------

**API Changes**

* Expose workflow_id and run_id to decision context.
* Initial workflow cancellation support.

* Add .cancel() method in ``WorkflowDefinition``.

* Add async ``cancellation_handler`` method that can be overwritten to
do cleanup for workflow cancellation tasks.

**Improvements**

* Implement workflow cancellation events.
* Big refactor of decider.py into a bunch of specific handlers
(ie. ``activity_task_handler.py``, etc.).
* Add separate future for cancel activity.
* Support ``RequestCancelActivityTaskFailedError``.
* ``ActivityWorker`` understands ``Cancellation`` / ``CancelledError``.
* Implement ``ActivityFuture`` that replaces the regular Future for
all activities and has SWF support for cancellations.
* Implement ``request_heartbeat()`` in Activity context.
* ``ActivityTaskHandler`` uses ``ActivityFuture``.

**Bugfixes**

* Add fallback handling for decoding of exception objects.
* Fix bug in workflow options overrides.
* Added kwarg formatting translation for Child workflow execution
trigger.
* Respect pagination token returned in SWF workflow execution history.
* Fixed bug with activities decorator kwargs not falling down to
enclosed activity decorators.

**Miscellaneous**

* Cleanup bogus prints.
* Doctype the async decorator a bit.
* Implement some integration tests.
* ``delete_decision()`` now returns True if a decision was deleted
successfully and False otherwise.
* Adjust handling of cancel events; parse exception out of event details.
* Cleanup of new handlers and decider.
* More activity cancellation work and more integration tests.
* Logic improvements + integration tests.
* Docstrings all around cancellation work.
* Refactor a bunch of cancellation related tests into a separate test file.

----------------

**API Changes**

* The worker API now uses ``botocore`` session, followed by region,
followed by domain, followed by default tasklist.

**Miscellaneous**

* Use BotoCore 0.66 which has lots of incompatible changes, therefore
the worker API changes as well.

----------------

**API Changes**

* Threading and multiprocessing based workers are renamed "Executor" and
accept a worker as an argument so that they can be used with either
the normal WorkflowWorker or GenericWorkflowWorker.

**New Features**

* Add GenericWorkflowWorker which allows specifying a function that
can use any method it wants to lookup workflow definitions from a
name and version, including by dynamically creating it.