Release v0.6 no models (#1355)

* Added missing meta file

* Removed the models from the LearningBrains

UnitySDK/Assets/ML-Agents/Examples/Basic/Brains/BasicLearning.asset

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UnitySDK/Assets/ML-Agents/Examples/Crawler/Brains/CrawlerDynamicLearning.asset

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UnitySDK/Assets/ML-Agents/Examples/GridWorld/Brains/GridWorldLearning.asset

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UnitySDK/Assets/ML-Agents/Examples/Pyramids/Brains/PyramidsLearning.asset

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UnitySDK/Assets/ML-Agents/Examples/Soccer/Brains/GoalieLearning.asset

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UnitySDK/Assets/ML-Agents/Examples/Soccer/Brains/StrikerLearning.asset

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UnitySDK/Assets/ML-Agents/Examples/3DBall/TFModels/3DBallHardLearning.tf.meta

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