Kwcoco

Fixed
* Handle deprecated `scipy.integrate.trapz`

Fixed

* CIFAR grabdata now converts train and test variants of the dataset and
includes channel information.

Removed
* Drop 3.6 and 3.7 support

Changed
* Optimize CocoObject1D get calls with SQL backends
* CocoObject1D.lookup with default now "works"-ish with SQL. Still experimental.

Fixed

* Added workaround for an issue where a postgresql cache of a coco dataset is unable to remember its original json filepath.
* Fixed issue with `CocoSqlDatabase.disconnect` where a session would be dereferenced, but not closed.
* Worked around issue in postgresql backend where track-ids were not decoded properly in their string form.

Added
* Add CLI for `find_unregistered_images`

Added
* Add `video_id` argument to `CocoDataset.annots`
* Can now specify render dictionary with `main_ext` and `main_channels` to `random_video_dset` to control demo data file format and the channel codes that are used.

Fixed:

* Prevent resource crash: `find_json_unserializable` now checks for circular references.

* Coco union now handles tracks.

Changed

* The `disjoint_tracks` in `CocoDataset.union` now works on a "track-name"
level. Old behavior where track-ids did not need a corresponding "track"
entry is still preserved but may be removed in the future.