Kwcoco

Added
* Ported channel related features to CocoImage
* vidshapes-msi is now an alias for vidshapes-multispectral
* Can now specify general channels for video toydata

Changed
* Split `kwcoco.demo.toydata` into `kwcoco.demo.toydata_image` and `kwcoco.demo.toydata_video`
* Moved code from `coco_dataset` to `_helpers`

Fixed
* Bug in `show_image` with MSI
* Fixed bug in ObjectList1D.peek

Added
* Moved Archive code to its own util module
* Extended channel slice syntax. Can now use "." to separate root from the slice notation.

Fixed
* Removed debugging print statements
* Fixed issue with pickling category tree
* Fixed bugs with numel and zero channels

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