[rllib] add augmented random search (#2714)

* added ars

* functioning ars with regression test

* added regression tests for ARs

* fixed default config for ARS

* ARS code runs, now time to test

* ARS working and tested, changed std deviation of meanstd filter to initialize to 1

* ARS working and tested, changed std deviation of meanstd filter to initialize to 1

* pep8 fixes

* removed unused linear model

* address comments

* more fixing comments

* post yapf

* fixed support failure

* Update LICENSE

* Update policies.py

* Update test_supported_spaces.py

* Update policies.py

* Update LICENSE

* Update test_supported_spaces.py

* Update policies.py

* Update policies.py

* Update filter.py

python/ray/rllib/test/test_supported_spaces.py

@@ -116,6 +116,13 @@ class ModelSupportedSpaces(unittest.TestCase):
                 "episodes_per_batch": 1,
                 "timesteps_per_batch": 1
             }, stats)
+        check_support(
+            "ARS", {
+                "num_workers": 1,
+                "noise_size": 10000000,
+                "num_deltas": 1,
+                "deltas_used": 1
+            }, stats)
         check_support("PG", {"num_workers": 1, "optimizer": {}}, stats)
         num_unexpected_errors = 0
         for (alg, a_name, o_name), stat in sorted(stats.items()):