Kwcoco

Added
* Add `.images` to `Videos` 1D object.
* Initial `copy_assets` behavior for kwcoco subset.

Changed
* Improved speed of repeated calls to FusedChannelSpec.coerce and normalize

Fixed
* Fixed bug in delayed image where nans did not correctly change size when warped
* Fixed bug in delayed image where warps were not applied correctly to concatenated objects

Added
* Initial implementation of shorthand channels
* Parameterized `max_speed` of toydata objects
* Add `combine_kwcoco_measures` function
* Add new API methods to ChannelSpec objects


Changed

* Reworking kwcoco channel spec backend implementation. Trying to maintain
compatibility and insert warnings where things might change.
* Removed six from CocoDataset
* Added support for pathlib


Fixed
* Fixed bug in union with relative paths

Added

* `ChannelSpec` can now be coerced from a `FusedChannelSpec`
* `FusedChannelSpec` now implements the `__set__` interface

Fixed
* Fixed bug when `track_id` is given to `add_annotation`
* Fixed but in `delayed_load` where requested channels were returned in the
wrong order, or with incorrect data.
* Bug in `delayed_load` where nans did not resize properly

Added
* Can now specify `-frames{num}` in demo names to control number of frames in each video


Changed

* In detection metrics, annotations now get a default score of 1.0 if not provided.
* In detection metrics, fixed AUC to report 1.0 when detections are perfect

Added

* Added `vidid` argument to `CocoDataset.images` 1D object mixin.
* Added `trackid` argument to `CocoDataset.annots` 1D object mixin.

Fixed

* `perterb_coco` now correctly perturbs segmentations

Changed

* Changed argument name from `gsize` to `image_size` in toydata methods.
Backwards compatibility is preserved via kwargs for now, but `gsize` will be
deprecated in the future.

Added

* CocoSQLDataset.coerce
* `kwcoco subset` CLI now has a `--select_images` and `--select_videos` option that takes a json query.
* Add initial implementation of `DelayedChannelStack.take_channels`, returns nans if the channel is not available.

Changed

* Made URIs for CocoSQLDataset slightly more robust
* kwcoco show now defaults `show_labels` to False