Remove future imports (#6724)

* Remove all __future__ imports from RLlib.

* Remove (object) again from tf_run_builder.py::TFRunBuilder.

* Fix 2xLINT warnings.

* Fix broken appo_policy import (must be appo_tf_policy)

* Remove future imports from all other ray files (not just RLlib).

* Remove future imports from all other ray files (not just RLlib).

* Remove future import blocks that contain `unicode_literals` as well.
Revert appo_tf_policy.py to appo_policy.py (belongs to another PR).

* Add two empty lines before Schedule class.

* Put back __future__ imports into determine_tests_to_run.py. Fails otherwise on a py2/print related error.

python/ray/experimental/array/distributed/__init__.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 from . import random
 from . import linalg
 from .core import (BLOCK_SIZE, DistArray, assemble, zeros, ones, copy, eye,

python/ray/experimental/array/distributed/core.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import numpy as np
 import ray.experimental.array.remote as ra
 import ray

python/ray/experimental/array/distributed/linalg.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import numpy as np
 import ray.experimental.array.remote as ra
 import ray

python/ray/experimental/array/distributed/random.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import numpy as np
 import ray.experimental.array.remote as ra
 import ray

python/ray/experimental/array/remote/__init__.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 from . import random
 from . import linalg
 from .core import (zeros, zeros_like, ones, eye, dot, vstack, hstack, subarray,

python/ray/experimental/array/remote/core.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import numpy as np
 import ray
 

python/ray/experimental/array/remote/linalg.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import numpy as np
 import ray
 

python/ray/experimental/array/remote/random.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import numpy as np
 import ray