Animalai

Added
- RayCast Observations.

Fixed
- Raycast length issue (less than diagonal arena length).

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Added
- Raycast observations.
- Agent global position tracking.

Changed
- Upgraded to ML-Agents release 2 (0.26.0).

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Added
- Ported Unity Environment from ml-agents 0.15 to 2.0.
- Ported basic python scripts from ml-agents 0.15 to 2.0.
- Added basic documentation.
- Added basic training scripts.
- Added basic training configurations.

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