Evaldet

Added

* HOTA metrics can now be computed, using the original matching algorithm from the paper (gives similar results, but does not correspond to TrackEval's implementation)

Added

* `Tracks` class, which represents the tracking data (detections), and provides loading functions to read from common MOT data formats
* `compute_mot_metrics` function, which can calculate MOT metrics (for now CLEARMOT and ID metrics, HOTA coming soon, ALTA in the pipeline)
* API documentation hosted on readthedocs
* Pypi package