Bluesky

Bug Fixes
* Revised behavior of magics that integrate with ophyd’s experimental “labels” feature. The most important difference is that the %wa magic now traverses the children of labeled devices to find any sub-devices that are positioners.

Bug Fixes
* Fixed race condition where monitored signals could emit an Event document before the corresponding Event Descriptor document.
* Addressed incompatibilities with upcoming release of Python, 3.7.

Features
* When used with ophyd v1.2.0 or later, emit Resource and Datum documents through the RunEngine. Previously, ophyd would insert these documents directly into a database. This left other consumers with only partial information (for example, missing file paths to externally-stored data) and no guarantees around synchronization. Now, ophyd need not interact with a database directly. All information flows through the RunEngine and out to any subscribed consumers in a deterministic order.
* New Msg commands, install_suspender and remove_suspender, allow plans to temporarily add and remove Suspenders.
* The RunEngine’s signal handling (i.e. Ctrl+C capturing) is now configurable. The RunEngine accepts a list of context_managers that it will enter and exit before and after running. By default, it has one context manager that handles Ctrl+C. To disable Ctrl+C handling, pass in an empty list instead. This can also be used to inject other custom behavior.
* Add new plans: x2x_scan(), spiral_square_plan(), and rel_spiral_square_plan().
* Add convenience methods for reviewing the available commands, commands() and print_command_registry().
* Add a crossings attribute to PeakStats.

Bug Fixes
* When resuming after a suspender, call resume() on all devices (if present).
* Fixed BEC LiveGrid plot for a motor with one step.
* A codepath in LiveFit that should have produced a warning produced an error instead.
Breaking Changes
* User-defined callbacks subscribed to the RunEngine 'all' stream must accept documents with names 'resource', 'datum' and 'bulk_datum'. It does not necessarily have to heed their contents, but it must not fall over if it receives one.
Deprecations
* The IPython “magics”, always marked as experimental, have been reworked. Instead of relying on the singleton lists, BlueskyMagics.positioners and BlueskyMagics.detectors, the magics now scrape the user namespace for objects that implement the _ophyd_labels_ interface. See IPython ‘Magics’ [Experimental] for the new usage. The magics will revert to their old behavior if the singleton lists are non-empty, but they will produce a warning. The old behavior will be

Features
* Refreshed documentation with a new Tutorial section.
* Extend scan() and rel_scan() to handle multiple motors, rendering inner_product_scan() and relative_inner_product_scan() redundant.
* A new plan stub, repeat(), repeats another plan N times with optional interleaved delays — a kind of customizable version of count().
* Better validation of user-defined per_step functions and more informative error messages to match.

Bug Fixes
* Fix axes orientation in LiveRaster.
* Make BestEffortCallback display multi-motor scans properly.
* Fix bug in ts_msg_hook() where it conflated month and minute. Also, include sub-second precision.
* Avoid situation where plan without hints caused the BestEffortCallback to error instead of do its best to guess useful behavior.
* Skip un-filled externally-stored data in LiveTable. This fixes a bug where it is expecting array data but gets UUID (datum_id) and errors out.
Deprecations
The caching_repeater() plan has been deprecated because it is incompatible with some preprocessors. It will be removed in a future release of bluesky. It was not documented in any previous releases and rarely if ever used, so the impact of this removal is expected to be low.

This release fixes small bugs in v1.0.0 and introduces one new feature. The API changes or deprecations are not expected to affect many users.

Enhancements
* Add a new command to the [RunEngine](http://nsls-ii.github.io/bluesky/run_engine_api.html#bluesky.run_engine.RunEngine), `'drop'`, which jettisons the currently active event bundle without saving. This is useful for workflows that generate many readings that can immediately be categorized as not useful by the plan and summarily discarded.
* Add `install_kicker()`, which dispatches automatically to `install_qt_kicker()` or `install_nb_kicker()` depending on the current matplotlib backend.

Bug Fixes
* Fix the hint for [inner_product_scan()](http://nsls-ii.github.io/bluesky/generated/bluesky.plans.inner_product_scan.html#bluesky.plans.inner_product_scan), which previously used a default hint that was incorrect.

API Changes
* In [tune_centroid()](http://nsls-ii.github.io/bluesky/generated/bluesky.plans.tune_centroid.html#bluesky.plans.tune_centroid), change the meaning of the `step_factor` parameter to be the factor to reduce the range of each successive iteration. Enforce bounds on the motion, and determine the centroid from each pass separately.
* The [SupplementalData](http://nsls-ii.github.io/bluesky/plans.html#bluesky.preprocessors.SupplementalData) preprocessor inserts its instructions in a more logical order: first baseline readings, then monitors, then flyers. Previously, the order was reversed.

Deprecations
* The suspender `SuspendInBand` has been renamed to [SuspendWhenOutsideBand](http://nsls-ii.github.io/bluesky/generated/bluesky.suspenders.SuspendWhenOutsideBand.html#bluesky.suspenders.SuspendWhenOutsideBand) to make its meaning more clear. Its behavior has not changed: it suspends when a value exits a given range. The original, confusing name now issues a warning.
* The suspender `SuspendOutBand`, which counter-intuitively suspends when a value enters a given range, has been deprecated. (If some application is found for this unusual scenario, the user can always implement a custom suspender to handle it.)

This tag marks an important release for bluesky, signifying the conclusion of the early development phase. From this point on, we intend that this project will be co-developed between multiple facilities. The 1.x series is planned to be a long-term-support release.

Bug Fixes
* `mv()` and `mvr()` now works on pseudopositioners.
* `reset_positions_wrapper()` now works on pseudopositioners.
* Plans given an empty detectors list, such as `count([])`, no longer break the `BestEffortCallback`.