* add OacAlgorithm and replicate paper results on HalfCheetah

* add oac_humannoid_conf and oac_algorithm_test

* minor updates in oac_algorithm_test

* address code reviews

* add oac halfcheetah and humanoid result figures

* update oac_algorithm test

* address further code reviews

* address further code reviews

* remove the unroll_with_grad

* update oac_halfcheetah_conf for better performance

* minor update of oac_halfcheetah_conf