Kwcoco

Added

* Ported the non-torch components of CategoryTree from ndsampler to kwcoco.
* This helps kwcoco work better as a standalone package.
* Union now works with videos
* New formal schema with jsonschema validation support
* Add `autobuild` kwarg to `CocoDset.subset`


Changed
* Removed optional dependency on ndsampler, functionality should now be available without ndsampler.


Fixed
* the `_check_index` method now works correctly.
* `add_image` with `video_id` now works even if the video doesn't exist yet.
* `add_annotation` no longer fails if `category_id` is None.

Added
* Added `compat_dataset.COCO` which supports 99% of the original `pycocotools` API.
* Added `kwcoco modify_categories` CLI which supports renaming and removal of categories.
* New `random_video_dset` demo function to generate toydata in video sequences. Added new tooling for this. STATUS: INCOMPLETE
* Add new video-based APIs to the CocoDataset based on the spec. STATUS: incomplete

Fixed
* Fix bug in find_representative_images.

Added
* Basic KW18 read/write/from-COCO support

Fixed
* Fixed json serialization error when using perterb_coco.

Added
* ported metrics from netharn, might be moved in the future.
* Add `perterb_coco`
* Add `CocoEvaluator` and CLI `kwcoco eval`

Added
* stats CLI can now accept multiple datasets.
* ported `data.grab_voc` and `data.grab_camvid` from netharn.
* Add `kwcoco.coco_evaluator.CocoEvaluator`
* Add `safe` kwarg to `CocoDataset.reroot`

Fixed
* Python2 error with json dump

Added
* Example usage section in CLI help
* Moved toydata from ndsampler to kwcoco

Fixed
* Multipolygon segmentations are now displayed correctly.
* Tracebacks on errors are now displayed.