Bluesky

Fixed
-----

* Updated the tests to use databroker.temp instead of sqlite databroker.
* ``xfail`` test that uses removed API.
* Fix ``list_grid_scan`` metadata for ``plan_pattern_args``.
* Fix descriptors for flyers that do not implement ``read_configuration``.

Enhancements
------------

* Do not pass the ``loop`` kwarg to ``RunEngine`` and ``RunBundler`` if we do
not have to.
* ``RunEngine``'s ``__call__`` now may return plan value, as toggled by new ``call_returns_result`` flag.
Default behavior has not changed, but may change in a future release.

Added
-----

* Enabled support of Python 3.9 and added it to the test matrix.

Documentation
-------------

* Update TOC links to blueskyproject.io.
* Added release instructions.
* Filled out ``README.md`` and added the ``description`` and
``long_description`` fields to ``setup.py``.

Fixed
- Fixed missing log output for CLI ZMQ proxy.
- Deprecated argument `logfile` of `bluesky.commandline.zmq_proxy.start_dispatcher`.
- Better behavior when zmq RemoteDispatcher receives malformed messages.

Enhancements
- Reorganized utils into subpackage, no API changes.
- Added `bluesky.utils.jupyter.NotebookProgressBar`.
- `bluesky.utils.PersistentDict` now inherits from `collections.abc.MutableMapping`.
- New module `bluesky.protocols` designed for type checking devices. See PEP 544.

Fixed
* Tweak layout of plots produced by the Best-Effort Callback when showing many LiveGrids.
* The bluesky.simulators.check_limits() simulator now calls obj.check_value() instead of looking at obj.limits.
* When a document is emitted from a RunEngine, a log message is always issued. Previously, Resource and Datum documents were missed.
* Various docstrings were fixed to match the actual function signatures.
* The utility bluesky.utils.is_movable() for checking with an object satifies the expected interfaced for a “movable” object now correctly treats the stop method and position attribute as optional.
* Documentation about the expected interface for “movable” objects was incomplete and has been revised to match reality.

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

Fixed

- `bluesky.utils.PersistentDict` has new methods `bluesky.utils.PersistentDict.reload()` and `bluesky.utils.PersistentDict.flush()` to syncing from and to disk. It flushes at garbage collection or system exit, which ensures that any values that have been mutated are updated on disk.

Fixed
* Allow `:` to be used in keynames and still format LiveTable.
* Address use of loop argument deprecated in Python 3.8.
* Ensure that `bluesky.utils` is importable from a background thread. (Do not create an instance of *~bluesky.utils.DefaultDuringTask* at import time.)

This release fixes a single regression introduced in v1.4.0. We recommend all users upgrade.

Bug Fixes

Fix a critical typo that made LiveGrid unusable.