Sleap

- Kalman filter-based tracking
- confidence map refinement fixes
- run eval after training
- other misc changes

Automated release of 1.0.4a7 on 2020-06-25

Automated release of 1.0.4a6 on 2020-06-25

Automated release of 1.0.4a5 on 2020-06-25

Automated release of 1.0.4a4 on 2020-06-25

Alpha release of 1.0.4.

- Automatic confidence map sigma scaling by output stride. Addresses quantization issues with integral regression.
- Add automatic evaluation after training.
- Initial Kalman filter tracking implementation.
- Fix tests, minor bugs and comments.